He arched his back, clenched both fists and roared at the Wembley sky.
That is what this meant to Arsene Wenger.
It was not just a roar of triumph, it was a roar of defiance, a roar of relief.
The defiance of a man who had just outperformed one of the younger, dynamic breed who are supposed to be consigning Wenger to the managerial history books.
The relief of a man who had just been reminded his players would still empty hearts and lungs for their cranky, ageing boss.
Heck, even Mesut Ozil looked like he had put in a shift, even Mesut Ozil looked like he had nothing left to give.
No wonder Wenger gave him a squeeze.
This was a triumph founded on toil, its roots in doggedness, its basis in character, its foundation in spirit, all the qualities Wenger is supposed to have sucked out of this squad.
Did fortune smile on him? It at least winked a few times.
David Silva, for 20 minutes shining like only he does, had to limp off, pointing a rightly accusing finger at his disabler, Gabriel.
Aguero tripped himself but, unpunished by Craig Pawson, with a little help from Alex Oxlade-Chamberlain in the penalty area.
An assistant referee’s errant, eagle eye adjudged Leroy Sane’s cross to have arced out before arcing in and being converted by both Sergio Aguero and Raheem Sterling for good measure.
Yaya Toure and Fernandinho, with foot and head, hit post and bar.
Yet Arsenal still had to do what they hardly ever do, chip out a comeback against a blue-chip opponent.
Having been set up to operate on the counter, they were caught on it, Toure robbing Aaron Ramsey with candy-taking comfort before sweetly sending Aguero into isolation.
The City striker raced on rails, Nacho Monreal into a headwind and Petr Cech’s positioning was an invite rather than an inconvenience.
Aguero, with polite excellence, accepted it.
That it proved to be Manchester City’s sole success was not just down to that sprinkling of fortune, it was down to the resilience of a defensive effort underpinned by the physical interventions - mainly legal, occasionally illegal - of Laurent Koscielny, Gabriel and Rob Holding.
It was a resilience that infused one of the most non-resilient teams of recent weeks. It was a backbone for the spineless.
Oxlade-Chamberlain was remorseless in his quest to make a difference and a difference he made when he persuaded a cross on to Monreal’s unfavoured but, this time, unerring boot.
Equality found not just on the scoreboard but on balance of play, extra-time became a tough one to call.
Vulnerability grew at both ends but the decisive moment came when Ozil sucked up enough oxygen to float a free-kick on to Koscielny’s knocking-down head and Sanchez finished after Danny Welbeck’s air shot.
Pep Guardiola - a first trophyless, managerial season looming - had tried most tricks, even a fourth substitute, but little worked, just as little has worked in so many of the truly challenging tasks he has faced this season.
Thursday and Jose could define his first English year.
For Wenger, an eighth FA Cup Final beckons, a seventh victory waits to be taken.
This, though, was about more than figures and records.
After the celebratory scream, Wenger momentarily threatened to go all Conte, Klopp and Pep, threatened to go emotional new school, threatened to march on to the pitch, man-hugs on his mind.
Thankfully, he saw sense but this was a day when he was grateful not just to reach a final … but to be finally sure each and every one of his men are, after all, standing squarely behind him.
No wonder he roared.