Aimar sends Benfica through after United fall apart at the back

Nani goes flying during a hard fought game with Benfica (EPA)

It was one of those games last night for Sir Alex Ferguson when whatever attacking storm his team created at one end of the pitch, it was matched by some form of calamity at the other and it means that Manchester United's Champions League lives are not guaranteed.

To be sure of a place in the knockout round they must get a draw against Basle in Switzerland on 7 December and in order to win Group C they will have to better the result that Benfica – already qualified for the next round – achieve in their final game against the Romanian champions Otelul Galati. It is not as difficult a situation as the one that their rivals Manchester City find themselves in, but it is hardly ideal.

As was the case in United's home game against Basle in this competition, there was far too much slack in Ferguson's defence for a team built in his traditions.

First Phil Jones scored an own goal within four minutes to put Benfica in front. Then, when Dimitar Berbatov and Darren Fletcher had given United the lead, mistakes from David De Gea and Rio Ferdinand meant it was tossed away.

There was no Wayne Rooney in this United team and, especially in the first half, they found themselves struggling to break free of Benfica's hard-working midfield. Their worry now is that they will not finish top of Group C – as Ferguson had warned in the build-up to the game – and that brings with it concerns over the likely opponents in the next round.

Even before United took the lead just before the hour it had turned into the kind of gripping game that makes the trudge through the Champions League group stages worthwhile. Their 2-1 advantage lasted barely a minute and the manner in which they conceded the equaliser was embarrassing for all those involved.

It started with a very poor clearance from De Gea and when Benfica moved the ball forward quickly Bruno Cesar got away down the right. Difficult though it was for Ferdinand to control a ball struck at him from such close range, the United defender succeeded only in blocking the ball with his groin. It was barely even a clearance and it fell to Pablo Aimar, who scored.

There were ten minutes at the end of the game for Javier Hernandez as United laid a familiar siege to Benfica's goal. But ultimately it was the Portuguese who went through to the next round and United who now face a difficult trip to Switzerland to finish the job.