Manchester United manager Sir Alex Ferguson said his side simply did not play well enough after they went down 2-1 to Bayern Munich tonight.
Wayne Rooney gave United the perfect start with a goal after just 64 seconds, but limped off in injury time of the Champions League quarter-final tie with an ankle injury.
"He's got a kick in the ankle, we'll just have to wait and see tomorrow," Ferguson said. "Hopefully it's not too serious.
"He may be doubtful for Saturday (against Chelsea), but it's too early to say."
As for tonight's game, Ferguson added on Sky Sports 2: "We didn't play well enough to be honest, we kept giving the ball away. We caused our own defeat.
"Bayern were the better team, we can't complain about that, but we're better than that in possession. We kept giving it away and that was our downfall.
"The first goal was a bit of luck with a deflection but the last goal, I don't know how you describe it. The game was done and we gave a terrible goal away."
The second leg is at Old Trafford next week and Ferguson added: "Old Trafford will be a different game obviously.
"We will be much better, no doubt about that, and hopefully we can recover.
"We have the away goal and we'll go out to win the game."