Now the stark reality of Arsenal's rank piece of carelessness, that defeat by Sevilla which cost them pole position in Champions' League Group H, returns to torment Arsène Wenger. Even "The Professor", a philosopher if ever there was one of footballing providence, and a man disinclined to indulge in hyperbole, accepts that Wednesday night, and the return at the San Siro in 13 days' time, represent a defining moment in Arsenal's European season. No matter that their opponents, Carlo Ancelotti's Milan, a club which claimed the trophy for a seventh time by beating Liverpool last season, are toiling in Serie A behind leaders and city rivals Internazionale.
"We have the toughest draw," Wenger views a fixture which, in effect, is the legacy of him deploying a below-strength side against the eventual group winners back in late November. "This game will define whether or not we can win the European Cup. On the other hand, two years ago we played Real Madrid and went through. Last year we played Eindhoven but went out. It's very difficult to predict what's going to happen. The only thing we do know is that if you don't play at your best against Milan, you're out."
Wednesday will be a night on which an absent friend will be remembered. What is difficult to gauge is the effect on the visitors of the probable passing of the finest Brazilian player of his generation from the live stage to the photographic gallery of greats. "Milan in shock", claimed Uefa's official website after Ronaldo travelled to Paris on Thursday for surgery to repair a tendon in his left knee damaged against Livorno. He left the pitch in tears. It is unlikely that we will witness him gracing this competition again.
Sentiment in football tends to be confined to the history books. Managers are more brutally pragmatic. Bill Shankly was not alone in regarding an injured player as simply this: out of sight, out of mind. Wenger is just being practical rather than heartless when he reflects: "Ronaldo is out, but I don't feel he was hyper-competitive, anyway. Of course he could still have come on but he was already over his best."
The Gunners manager is rather more troubled by the presence of Ronaldo's compatriot, Kaka. "He made the difference last year in this competition," says Wenger. "He scored 10 goals in 11 games. He made the difference against Celtic [scoring the extra-time winner in last season's last-16 tie]. Kaka is the guy who can dominate a situation and in 10 seconds get to the other side of the box and score a goal. We need to be more cautious in the centre than we usually are. He is especially dangerous at counter-attacking."
It is a confrontation luxurious in promise, as Arsenal's young performers, whose rich quality of football and a corresponding vein of form have provided a mocking response to those sceptics who claimed it was premature for them to wrest the Premier League title from Manchester United. Now they seek to demonstrate they can replicate that form in Europe.
Ahead are two nights on which key performers, including Emmanuel Adebayor, Cesc Fabregas, Mathieu Flamini and Alexander Hleb, have to measure their progress against men like Andrea Pirlo, Clarence Seedorf, Cafu and that redoubtable figure of Gennaro Gattuso. Flamini, in particular, has emerged as an inspirational component in the Arsenal engine.
"He has a similar style to Gattuso because of the size and he's always up for it," says his manager. "Mathieu is mentally strong and is a winner. Players who never give up mentally always improve. He's responsible for the tempo in our game."
However, Wenger adds: "We are underdogs by a little bit. They [Milan] have the experience and won it last year. We are an upcoming team, so it is a big challenge against the holders."
Wenger knows that an elusive Champions' League trophy arriving at The Emirates would complete an already remarkable CV. It would also bring him something approaching immortality in north London.
"My objective is to achieve as much as I can for the club rather than becoming immortal," he retorts. "I know that no matter how immortal I become, I will die anyway. What advantage is it to you to be remembered after you're dead?"
He adds: "I am under pressure to deliver any trophy. I want to win the Champions' League because it's prestigious."
As for emulating his long-time adversary, Sir Alex Ferguson, and claiming a treble, the Frenchman dismisses the concept. "It's nearly impossible now to challenge on the three fronts – Champions' League, Premier League and FA Cup – unless you have a massive squad. But we don't have that. Teams like Manchester United have done it before but maybe it's more difficult now than in 1999..."
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