Two losses in their previous four league games as seen the Blues' lead at the top cut to four points, while Tottenham's club-record seven Premier League wins on the trot sees them boosted by superior momentum.
The two teams traded wins on home ground in the league earlier this season, Chelsea's 2-1 win at Stamford Bridge followed by Tottenham 2-0 victory at White Hart Lane in January, and have similarly equal records in the FA Cup, with the Blues boasting five wins to Spurs' four.
Despite the rivalry, both sets of players will come together to pay tribute to Ugo Ehiogu after the Spurs under-23s coach passed away following his collapse at training on Thursday.
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Chelsea and Tottenham meet at Wembley Stadium in the FA Cup semi-final with kick-off scheduled for 5.15pm on Saturday, April 22.
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Defender Gary Cahill is almost certainly out of Chelsea's FA Cup semi-final with Tottenham at Wembley on Saturday due to illness.
Cahill was admitted to hospital this week with gastroenteritis, with Nathan Ake and Kurt Zouma possible replacements and John Terry likely to be on the substitutes' bench.
Goalkeeper Thibaut Courtois is available again following an ankle injury which saw him miss last Sunday's loss at Manchester United.
Provisional squad: Courtois, Begovic, Fabregas, Zouma, Alonso, Kante, Hazard, Loftus-Cheek, Moses, Pedro, Costa, Matic, Willian, Batshuayi, Terry, Azpilicueta, Chalobah, Luiz, Eduardo, Aina, Ake.
Tottenham defender Danny Rose will not recover in time for the semi-final.
Rose has begun training again after missing almost three months with a knee injury but the full-back will not make the clash.
Erik Lamela and Harry Winks are both out with hip and ankle injuries respectively while goalkeeper Michel Vorm is also unavailable with a knee problem.
Provisional squad: Lloris, Lopez, Whiteman, Davies, Alderweireld, Vertonghen, Dier, Wimmer, Walker, Trippier, Wanyama, Dembele, Eriksen, Alli, Sissoko, Onomah, Son, Janssen, Kane.
Chelsea starting XI: Courtois; Azpilicueta, Luiz, Ake; Moses, Kante, Matic, Alonso; Pedro, Hazard; Costa
Tottenham starting XI: Lloris; Walker, Alderweireld, Vertonghen, Davies; Dembele, Wanyama; Eriksen, Alli, Son; Kane
BETTING ODDS (via 888 Sport)
- Chelsea to win in 90 mins: 7/5
- Tottenham to win in 90 mins: 8/5
- Chelsea to win after extra time: 14/1
- Tottenham to win after extra time: 15/1
- Chelsea to win on penalties: 10/1
- Tottenham to win on penalties: 11/1
Click here to place a bet. Odds correct as of April 21 at 9pm.