Dimitar Berbatov is fit for United's trip to Stamford Bridge, although Sir Alex admits he faces a selection dilemma when it comes to Cristiano Ronaldo.
Ronaldo played 28 minutes on Wednesday against Villarreal and the Reds boss told media on Friday he would have no fears in picking him in Sunday's side.
â€œHe's a natural athlete,â€ Sir Alex said. â€œHe's trained very well and I'd have no problems at all playing him on Sunday. I just have to decide if it's the right time.
â€œI think he did very well on Wednesday night. He was aggressive in his running and was a good threat.
"When Ronaldo's really buzzing he wants the ball and he attacks defenders straight away with such speed that they're forced to back off. That was the case on Wednesday.
"He was on fire and really revved up to perform well. That surprised me given he's had an operation and he's been in rehabilitation for the last two months and hadn't played since 21 May. It was a big ask but you have to say his performance was outstanding.
â€œThe boy wants to play at Chelsea â€“ he's been in my ear the whole time. I just hope I pick the right team."
Everybody else came through Wednesday's game unscathed, with Sir Alex confirming the only absentees for Sunday will be Michael Carrick (ankle) and Nemanja Vidic (suspended).
The manager admitted losing to Liverpool last weekend was â€œa disappointing resultâ€ and underlined Sunday's trip to Stamford Bridge was a must-win.
â€œWhen you play against the big four it's important you get a big points-haul out of
them. Last season we did very well against the top four. This season we've lost the first one already [at Anfield]. We can't afford to lose another one.â€
Despite a slow start to the season, Sir Alex insisted there is no need for panic just yet.
"I don't see Sunday's game as a test of character for my team. That's been well established already â€“ there are no doubts in that department.
"What this team has to do, like many Manchester United teams have done over the years, is recover from a bad defeat. We've got to make sure we come away from Chelsea with a win.
"It's a great challenge to us and a lot of people don't expect us to win, which is unusual for this club. That's the challenge: let's get on with it."
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