This was Robin van Persie we are talking about here, the man who has kept the enterprise alive for much of this dark season, the player whose goals have been at times the one spark of optimism, the forward who, as his magnificent penalty in the first half demonstrated, simply does not miss. Four-nil down from the first leg, the most improbable comeback in the club's stellar history appeared about to be engineered. If anyone could do it, Robin could.
But the miracle did not come about. Van Persie equivocated. Instead of slamming the ball home, he tried deftly to chip it over the prostrate Christian Abbiati. But the Milan keeper lifted an arm and somehow kept the ball out. The chance was gone. And in front of the press box, several of the home fans, who had spent the match living on the very edge of their nerves, looked in urgent need of attention from St John Ambulance personnel.
In a sense, that the ice-cool finisher Van Persie, the man who never misses, should miss at that point somehow sums up Arsenal this season: you really cannot predict an outcome involving this outfit. At times woeful — as in the first leg in San Siro — at times magnificent — as in the first half of the second leg at the Emirates - the one thing they never are is consistent. How bookies must love them: No-one knows what will happen.
But at least what the performance did do was provide ample demonstration that Arsene Wenger is not, after all, a lone, bonkers voice howling Lear-like into the abyss. All season he has talked about his team's character. All season we have wondered what he was talking about, following his words but not understanding their meaning.
Here, though, they showed a depth of resolve few could have predicted. And what a change it wrought at the Emirates. The self-same regulars who had poured scorn at Wenger during the home defeat by Manchester United (remember the chant of "you don't know what you're doing" directed at the finest manager in the club's history?) the same bunch who had fulminated against Theo Walcott in the first twenty minutes against Spurs ("get him off, get him off, get him off") cheered the team throatily and mightily for 90 minutes, then applauded them off at the end with a consolation ovation which must have been heard in Tottenham. The collective was fully restored.
It had been coming. It was evident in the home game against Spurs. It was there in the away win at Anfield. And it was really a matter of the other players delivering the same kind of performance as Van Persie. All season he has been doing it, at times all alone. Against Spurs, though, he was joined by Walcott and Rosicky. Against Liverpool up stepped Szczesny. Last night it was all three of them, plus the wonderful, electric-heeled Alex Oxlade Chamberlain, who surely ran and jinked and shimmied himself into an England shirt. And for once the back four — albeit confronted by an under-whelming Milan side in which Zlatan Ibrahimovic gave a passable impression of a bad Andy Carroll — joined in the party.
Suddenly, with all of them firing Wenger looked as if he had a team.
But not, sadly, a squad. In the first hour, Arsenal were terrific. Chances were created, three goals were scored, Van Persie looked as if he would fulfil the terrace boast and score when he wanted. But once Walcott and Chamberlain had succumbed to injury and fatigue midway through the second half and were replaced by Park and Chamakh you knew it was over. Only one goal was needed to keep the tie alive, but frankly that front two could play for a year and not deliver the crucial strike.
So where does that leave Arsenal? Well, momentum is clearly on their side. They have won their last four Premier League games to make a bold and plausible bid for a Champions League place. Wenger wants third and given the stumbles at White Hart Lane and the endless cultural revolution at Stamford Bridge it is now more than possible.
Mind, even if he achieves that it won't address some of his more fundamental problems. The weakness in the squad will still be there. The manager will need recourse to the transfer market this summer to patch up in defence, midfield and attack. And most importantly, if he is to convince the fans they have any hope in the future, he will have to ensure Van Persie remains. That miss at the death last night was an aberration. The very fact Arsenal have climbed so far from such depths this season is entirely down to him. Now the skipper has righted the sinking ship, he needs to be at the helm as it steams full ahead.