Raducanu dropped just four games in a ruthless display
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US Open champ to play Azarenka in the second round
Emma Raducanu showed shades of the level that earned her a maiden grand slam title as she handed Serena Williams a 'bagel' in a comfortable straight sets win at the Western and Southern Open.
It was a near-perfect match from the British No 1, recording just one unforced error in a 6-4, 6-0 win in front of a sold-out crowd in Cincinnati, Ohio.
For Williams, this was another setback as she gets set to bid farewell to the sport at the US Open, which begins on August 29. After the pair shook hands at the net, Williams packed her bags and swiftly left the court, declining an on-court interview request and thwarting plans by the tournament to pay tribute to her.
Raducanu entered the match with back-to-back defeats and question marks about the upcoming defence of her title in New York. But she made a fast start here, breaking Williams to love in the opening game and racing into a 4-1 with a double break.
Williams showed some signs of her all-conquering best, getting one of the breaks back and forcing Raducanu to serve for the set but the Briton was coolness personified, hitting an ace to seal it.
Watch: It's 'a gift' to play Serena Williams, says Raducanu
In years gone by, you would have expected a response from Williams, a two-time winner of the event.
But there was no such recovery as Raducanu broke Williams' ailing serve again at the start of the second set and never looked back. The 19-year-old sealed victory when Williams put one last return into the net and earned what she will hope is a momentum-building win ahead of the US Open.
Sensing the moment, not just for her but also for Williams, there were no wild celebration from Raducanu, who gave a reserved fist pump in the direction of her support box, which included Russian coach Dmitry Tursunov, who remains on trial with her this week.
With Williams' quick exit, the floor was left for Raducanu to pay tribute to Williams, who has one win in her last three tournaments.
“I think we all need to just honour Serena and her amazing career,” said Raducanu. “I’m so grateful for this experience to play her and for our careers to have crossed over. Everything she achieved is inspirational and it was a true honour to share the court with her.
"The atmosphere tonight was amazing. Even when you guys (the crowd) were cheering for her, I was all for it.
"I was nervous from the first point to the last point, she can come back from anything and I was pleased I was able to keep my composure."
Next up for Raducanu is former world No 1 Victoria Azarenka in the second round on Wednesday evening and if she can maintain this level of performance and clinical edge, she could put herself in a strong position going into the final grand slam of the year.
Watch: Match highlights
Emma Raducanu beats Serena Williams, as it happened
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It may not have been the thriller we were hoping for but Raducanu that was a much-needed win which could be the spark that reignites her season.
For Williams, another defeat and more questions than answers as she heads to the US Open for what will surely be her final tournament.
Relive the match below and read my report from the match above.
To be honest I was nervous from the first point to the last point because I know what a champion she is, she can come back from any situation and I’m just so pleased I could keep my composure.
Concern for Williams
Some suggestions Williams may have been carrying a knee injury going into the match. That could explain her struggles on serve but she was largely outplayed tonight.
And any hopes of a farewell in New York look very slim.
More from Raducanu
I’m so grateful to have been able to play her and for our careers to cross over. It was a true honour to share the court with her
Just one unforced error by Raducanu tonight according to the stats.
Super impressive match and a lot of positives to take.
Raducanu pays tribute to Williams
I think we need to just honour Serena and her amazing career.
Williams makes a quick exit, someone tries to get her to speak but she appears to decline and couldn't leave the court faster.
Raducanu 6-4, 6-0 Williams* (*denotes next server)
Williams forehand return long, 15-0. Williams forehand winner, 15-15. Williams frames a forehand return long, 30-15.
Raducanu forehand winner down the line, 40-0. Three match points.
Williams forehand into the net, GAME SET MATCH RADUCANU.
'Thank you, great match' Williams says.
Raducanu* 6-4, 5-0 Williams (*denotes next server)
Williams' backhand has let her down tonight and another error into the tramlines makes it 15-15.
Williams overhead winner, 30-15. Huge Raducanu forehand up the middle and Williams can't handle the pace, 30-30.
Point of the match as Raducanu shows great hustle to stay in the rally but Williams eventually finishes with a forehand winner, 40-30. Williams double fault, deuce. Williams backhand long, break point.
Brilliant from Raducanu. Williams hits a wide serve but Raducanu reads it and nails a backhand cross court winner to break.
She will serve for the match next.
Raducanu 6-4, 4-0 Williams* (*denotes next server)
More like it from Williams as she takes charge of the point and finishes with a forehand winner, 0-15.
Three errors by Williams allows Raducanu to move to 40-15. And Raducanu holds after another Williams error.
Raducanu* 6-4, 3-0 Williams (*denotes next server)
Williams backhand clips the top of the net, Raducanu chases down the short ball and hits a deft drop shot, 0-30.
Williams double fault, three break points. Williams saves the first with an ace. Then the second with an overhead winner. But not the third as Raducanu goes on the attack and finishes with a forehand winner.
Double break for the Briton.
Raducanu 6-4, 2-0 Williams* (*denotes next server)
Such good tennis from Raducanu as she dominates from the baseline and puts away a forehand winner, 15-15.
Raducanu ace, 40-15. Williams forehand long and Raducanu consolidates the break.
Second Set: Raducanu* 6-4, 1-0 Williams (*denotes next server)
Timely ace from Williams, 15-15. But she inexplicably puts a backhand long, 15-30. Williams forehand into the net after a deep Raducanu return. Break point.
Good defence by Raducanu and Williams impatiently puts a backhand long.
Another break for Raducanu.
Raducanu 6-4 Williams* (*denotes next server)
Wide ace by Raducanu to open the game. 'Come on' from Raducanu as she steps forward and hits a forehand winner down the line, 30-0.
Another dominant rally from Raducanu and Williams puts a forehand long, 40-0. Three set points.
Ace by Raducanu down the T. Exceptional tennis by Raducanu.
Raducanu* 5-4 Williams (*denotes next server)
Ace No 5 for Williams as she moves to 30-15. Raducanu bullies Williams with a series of deep backhands and gets the error from the American.
Williams forehand into tramlines, set point Raducanu. Williams forehand winner, deuce.
Williams' serve comes back to her and allows her to hold and force Raducanu to hold her own to win the set.
Raducanu 5-3 Williams* (*denotes next server)
Important service game for Raducanu with Williams gaining some momentum now.
Williams nets an attempted forehand pass, 30-0. Good, measured tennis by Raducanu as she hits a forehand winner, 40-0.
Williams nets a backhand return and Raducanu wins her most comfortable service game of the match.
Raducanu* 4-3 Williams (*denotes next server)
Back-to-back errors by Williams, 0-30. She responds with an ace, 15-30. Then another backhand winner after a huge first serve.
Big ace down the T from Williams, 40-30. Third ace of the match by Williams.
We have a game now folks.
Raducanu 4-2 Williams* (*denotes next server)
The crowd are trying to lift Williams but the American looks a bit deflated at this stage of the match.
Williams goes for it with a return but Raducanu gets the ball back in play and Williams nets a backhand, 30-15.
Williams continues to misfire as she places a backhand wide, 40-15. First deuce of the match as Williams hits a forehand winner.
Williams then steps in and hits a forehand winner off a Raducanu second serve, break point.
"Come on" shouts Williams as she breaks for the first time when she dominates the rally and Raducanu's defensive forehand goes out.
Raducanu* 4-1 Williams (*denotes next server)
Williams roars with frustration as she hits another double fault, 15-30. Superb backhand up the line by Raducanu, 15-40. Raducanu is keeping her cool and delivering on the court.
Williams ace, her first of the match, saves the first break point. But Raducanu gets the second break after 17 minutes when Williams puts a forehand long.
Raducanu 3-1 Williams* (*denotes next server)
First sign of Williams' magic as she hits a gorgeous drop shot winner, 15-15. Raducanu never saw it coming.
Raducanu responds with an ace, 30-15. Another ace from Raducanu and she holds. Brilliant early serving from the Briton.
Raducanu* 2-1 Williams (*denotes next server)
Better from Williams as she gets Raducanu on the run now and Raducanu puts a defensive backhand long, 30-0.
Williams does get on the scoreboard with a hold to 15. The fans like that!
Raducanu 2-0 Williams* (*denotes next server)
Williams' erratic start continues as she places a volley wide, 15-0. Lovely point by Raducanu as she gets Wiliams on the run and puts away a cross court forehand winner, 30-15.
Williams forehand return long, 40-15. Another Williams backhand error.
Ideal start by the US Open champ.
First Set: Emma Raducanu* 1-0 Serena Williams (*denotes next server)
Clean hitting from both players on the opening point before Williams nets a backhand. Another error by Williams and it's 0-30.
Williams double fault, second serve was well long. Three break points. And Raducanu gets the early break when Williams nets a backhand.
An error strewn start by the American.
Greg Rusedski and Martina Navratilova both go for Raducanu citing Williams' lack of match fitness.
Early win for Williams as she wins the coin toss and opts to serve first.
Here we go!
We see Raducanu, standing alone, waiting for Williams to come down the tunnel.
After a minute or so, both players are ready and are announced onto court. An incredible reception for Williams in what might be her final match in Cincinnati.
Kyrgios has been asked if he will be watching...
I probably won’t to be brutally honest. Not that I’m not a fan of tennis and those two amazing players.
Let's hope he will follow the match here!
First sighting of Williams
The cameras have captured Williams in the tunnel warming up.
The American is getting the blood pumping with some skipping exercises.
Clash of the generations
Raducanu has described the chance to play Serena Williams before the 23-time grand-slam singles champion retires as a "great gift".
Raducanu faces Williams in the first round of the Western and Southern Open in Cincinnati, which is likely to be the American's final tournament before the US Open, where the Briton is the defending champion.
Williams has indicated she will retire after competing at Flushing Meadows, the 40-year-old saying she was "evolving away from tennis, toward other things that are important to me".
I think it's gonna be an exciting match. I'm looking forward to it. It's an amazing opportunity to play probably the best tennis player of all time. It's probably going to be my last opportunity to ever play her.I think that, for our careers to have crossed over, I think I'm really fortunate that I get to play her. Whatever happens, I think it's gonna be a really good experience for me and something that I will remember for the rest of her life.Expectations, I don't really know, I don't really care. I just want to go out there and, one, enjoy the match that I'm going to play whenever I do play it.It's a great gift to play the best on her way out from the sport. So I'm just looking forward to that.
I'm hearing the courts are being dried as we speak so we shouldn't be delayed too long.
Tale of the tape
Williams: 40 years old, 23 grand slams, 855 wins, 73 titles
Raducanu, 19 years old, 1 grand slam, 87 wins, 1 title
We were expecting Raducanu and Williams to arrive on court at around midnight. But we have some unexpected rain in Cincinnati so we could be delayed.
Unlike Wimbledon where court covers are used, in America when the rain falls they use towels and a big drying machine!
Welcome to our live coverage of Emma Raducanu vs Serena Williams in the first round of the Cincinnati Open.
It is the first meeting between the pair and comes at a tournament which stands as a key warm-up event for the US Open.
Raducanu's form has been up-and-down since her stunning triumph at Flushing Meadows last year and she will be desperate for things to click into place ahead of her title defence.
Since last year's US Open, the Briton has played in 16 tournaments and been knocked out by a lower-ranked player 14 times.
The Briton, who currently sits at No 10 in the world rankings, said the chance to play "the best of all time" was "a great gift".
"I think it's gonna be an exciting match," Raducanu said in the buildup. "I'm looking forward to it. It's an amazing opportunity to play probably the best tennis player of all time. It's probably going to be my last opportunity to ever play her.
"I think that, for our careers to have crossed over, I think I'm really fortunate that I get to play her. Whatever happens, I think it's gonna be a really good experience for me and something that I will remember for the rest of her life.
"Expectations, I don't really know, I don't really care. I just want to go out there and, one, enjoy the match that I'm going to play whenever I do play it.
"It's a great gift to play the best on her way out from the sport. So I'm just looking forward to that."
Raducanu's historic win at Flushing Meadows came 22 years after Williams won her first major singles title in New York, aged just 17.
The winner of the match between Raducanu and Williams will face Victoria Azarenka in the second round after the Belarussian overcame Kaia Kanepi in three sets.