It was the day when Arsenal finally knew what they were doing on the big stage once again.
They had a mission. They had had a tactical plan. They had desire, purpose and self-belief.
They even dug in and defended well to deservedly defeat Manchester City in the FA Cup semi-final and secure an all-London final against Chelsea on May 27.
In short, in Arsene Wenger, they had a manager back in command of things after the most torrid spell of his 21 years with the club.
It is fair enough to ask why the qualities so impressively on display this time around have been so glaringly absent for so long this season.
One win can't make the doubts go away completely, but the team and the manager responded well to their troubles against City. If it helps them work out how to make things this way every weekend, a major turning point may have been reached.
Up in the stands at Wembley, there was barely a thought given to the on-going ‘Wenger Out’ campaign while the euphoria of a significant victory swept around the place.
It may resume in these final weeks of the Premier League season; it may not.
But there was little doubt on Sunday afternoon that on this occasion at least, Wenger had delivered some fresh evidence to back up the self-confidence which will prompt him to imminently commit himself to two more years in charge at the Emirates.
The fact that he out-plotted the stuttering genius, Pep Guardiola, will be another reminder that Wenger may still have something to offer, even at 67.
Across north London, the fact that Arsenal deserved their victory in the spring sunshine may only have made this a more difficult weekend to bear for Tottenham's disappointed supporters.
Quite plainly, their side did not get what they deserved from this semi-final weekend.
Spurs were the better team against Chelsea on Saturday but still found a way to lose - or, more charitably, were beaten by a club who are old hands at finding a way to win against the odds.
Antonio Conte's side will rumble on now towards a potential league and cup double re-assured that they can still get results even during their first minor wobble since last autumn.
What Spurs have to do is the toughest mental job of all amid the fall-out of this weekend settles.
They are a young side but they have experienced disappointment before after falling at the final hurdles of last season's title race.
With another dose of such bitter seasoning inflicted upon them at Wembley on Saturday, they have to simply suck it up and make it work for them.
That is the only response which will ensure they keep up their pursuit of Chelsea in these remaining weeks of the title race.
They have been bursting with rampant self-belief in recent weeks. And it hardly requires a master coach and motivator to tell them that this is professional sport and that you don't always get what you deserve.
So it is self-evident that they have to haul themselves off the floor. But just in case there is a problem, Tottenham already have Mauricio Pochettino.
At Wembley on Sunday, meanwhile, Wenger could finally allow himself a public smile again. And he dropped a hint about his on-going commitment to his club.
He may have been a little late in joining in with the fashion for playing three at the back, with wing-backs getting forward. But it worked excellently against City, with Alex Oxlade-Chamberlain, so often a vague, uncertain presence, delivering a superb performance in the role.
After several weeks of corrosive defensive uncertainty which had only ended against a meek Middlesbrough eight days earlier, the performance of Gabriel in particular restored the idea that Arsenal can be resolute against sharper opposition too.
Finally, the timely introduction of Danny Welbeck proved to be a clever stroke by Wenger as well. His finishing touch was questionable; his value as a major worry for City's defenders around the box was not.
It was Welbeck's mis-kick which set up Alexis Sanchez's winner, but it was his presence which counted. That is often the way in the harum-scarum world of English football.
Wenger knows that well enough after 21 years. Finally, he got his team to respond and take charge of things once again. It may mean he will be around for a while yet.