Animated Wenger forces Ferguson on to back foot

This was supposed to be a piece contributing to the debate over the demise of Arsenal. Instead its title theme should now be: just what's up with Manchester United? What a difference 90 minutes makes. Maybe that would take too much away from the power of Arsenal's performance. If last week's defeat by Stoke City was a watershed – a soul-searching, future-defining, where-do-we-go-from-here moment, even if Arsène Wenger called it an "accident" that had provoked "hysteria" – then so was yesterday's victory.

At the Britannia Stadium, Wenger had been passive throughout and remained seated in the dug-out, arms crossed. And so, in effect, were his team.

This time he stood. He didn't take his seat once. He cajoled, pleaded and, in the opening 10 minutes when United appeared likely to run riot, prayed. Now and again he adopted that trademark crouched position as he silently pleaded. He rocked on the balls of his feet and attempted to wring every bit of effort from his team, his players who were carrying not just a club but a football philosophy and one man – Wenger's – set of beliefs and reasons for being, on to the pitch.

When put like that then it's barely a surprise that they won what turned into one of those epic contests whose result and content often reverberate throughout the rest of the campaign. Fantasy football, Sir Alex Ferguson called it, and that wasn't necessarily said in praise, rather wonderment. And, for United, a great setback to their attempts to win a third successive Premier League title.

OK, Arsenal have lost against Stoke, Hull and Fulham, unthinkable at the start of the season, but United have been defeated by two of their Big Four rivals, while gathering a draw at Chelsea. All were away from Old Trafford, which will be used as an argument in support of their credentials to turn things around, but Ferguson will need to analyse what went wrong.

Bad luck, for sure, contributed. United, probably, had more chances. But nothing ran for them until Rafael da Silva – a chirpy, impressive replacement for the sluggish Gary Neville – smashed in his 90th-minute volley. There was a catalogue of misses. Wayne Rooney, out of sorts, shot woefully over in the first half and appeared to let the annoyance of that miss, and a trip on him by Cesc Fabregas, pursue him throughout the rest of his involvement.

Then there was Cristiano Ronaldo's back-post volley, off his heel rather than his instep, immediately after Samir Nasri's second goal while, time and again, crosses were overhit or aimed at the wrong target – chipped to Carlos Tevez rather than Dimitar Berbatov – which all contributed to a feeling that United are not quite on the mark this season. Too often they have either failed to take advantage or allowed that to slip.

There is not a relentless efficiency to their football. Opportunities seem to have to come in two and threes for one to eventually be taken. The calibrations were all wrong. They were off the pace, quite literally, as Fabregas, Denilson and Nasri buzzed around them. Arsenal seemed more determined. Incredibly, more aggressive.

Ferguson will have to examine all this – from the lack of certainty in Edwin van der Sar's play, a weak punch straight to Abou Diaby was simply shocking, to Neville's lack of fitness to worryingly unconvincing performances from Anderson, Michael Carrick and Ronaldo while Tevez cut a frustrated figure. Rooney? He just saw red – and would have been in danger of seeing red had he remained on the pitch.

There's certainly no crisis at United. Their riches are too great and they will, surely, be running Chelsea and Liverpool close this season. And maybe Arsenal, also, which wasn't what was expected to be said this morning. But United need to find more pattern to their play, a little more certainty to their approach or they are in danger of leaving themselves in an almighty game of catch-up which, with what they have available to them, isn't where they should be right now.

"It's football and we were talking about it yesterday," shrugged Fabregas when he ignored an invitation to talk about Arsenal's difficulties and just how important a victory it was. True, but the significance of it all was there in the raging pride and relief in his eyes. "It changes so quickly," the young midfielder added. In 90 minutes (plus injury time) in fact.