Rooney's dream start ends in United tears

Ankle injury may end striker's club season and raises World Cup fear as Bayern snatch late 2-1 win

Wayne Rooney's season for Manchester United could be over after he suffered a suspected sprained ankle in the Champions League quarter-final first-leg tie in Germany last night. The injury inevitably raises concern as to his fitness for England's World Cup campaign which opens in less than 11 weeks' time.

Rooney left the Allianz Arena on crutches with his right foot in a protective boot. He will be assessed before United fly home today. His injury capped a bad night for the Premier League champions who lost 2-1 to Bayern Munich despite taking a 64th-second lead. That goal was scored by Rooney, his 34th of a prolific season, underlining his importance for club and country.

In the immediate aftermath of the match Sir Alex Ferguson was unable to offer much insight into the severity of the injury which occurred in the build-up to Bayern's injury-time winner.

"It's maybe not too serious, we can't say," he said. "He's hurt his ankle but it's too early to say how badly. I don't think it is terribly serious but it is too early to say."

Ferguson added that he did not know if Rooney would be fit for United's Premier League summit meeting against Chelsea on Saturday lunchtime. The prospect of his appearing at Old Trafford even for next week's second leg with Bayern would seem very optimistic. Rooney was in agony when he was carried from the pitch – and this is a footballer with a high pain threshold. He appeared to turn his right ankle as he reacted to having his left foot trodden on by Bayern's Mario Gomez.

There is no set time for recovery from an ankle sprain, it depends on the severity of the injury. Bupa's website says: "It can take between a few weeks and a year to fully recover. Mild sprains start to get better after a few days. Within six to eight weeks you should be able to put your full weight on your ankle without any pain when walking.

"If your sprain is mild, you can start doing some sport again once the swelling has gone down. This could be after a week for swimming but longer for activities that put more pressure on your ankle. With more severe sprains your recovery period may take up to 12 months."

The Premier League concludes on 9 May, less than six weeks' time. The Champions League final is on 22 May with England beginning their World Cup campaign against the United States on 12 June.

Rooney went into England's last World Cup unfit after suffering a foot injury late in the season. He was invalided out of Euro 2004 after breaking a metatarsal in the quarter-final defeat to Portugal.

His value to United was underlined by the winning coach last night. "Rooney is their most important player," said Louis van Gaal. "Look at the statistics. Before the weekend their second top scorer was own goals."

Rooney's injury aside Ferguson was also disappointed at United's performance. "We gave the ball away and caused our own defeat," he said. "Right from minute one the possession wasn't our standard. It's hard to explain because it is something we pride ourselves on and it has been integral to our progress this year. Bayern were the best team. We can't complain about that."

With Bayern in control Ferguson admitted Edwin van der Sar "kept us in the game with fantastic saves." He was finally beaten by a Franck Ribéry free-kick, deflected off Rooney, with 14 minutes left. Then Ivica Olic took advantage of an error by Patrice Evra to score in the 92nd minute. "It was not a good goal to lose," said Ferguson.

"The tie is not dead," he added. "It's always an advantage to score away from home. Bayern have a strong chance but on our own ground we should be confident enough to have a real chance of progress."