Alex Ferguson has stated that tonight’s second-leg Champions League semi-final against Shalke is just as important as Sunday’s clash with Chelsea.

The Red Devils go into tonight’s match with a 2-0 advantage and are heavy favourites to go through to the final. However, a Premiership clash with Chelsea on Sunday is forcing Ferguson to rest key players in preparation.

He compared the situation to last year, when United lost to Chelsea days after a Champions League meeting with Bayern Munich.

“If you look at our experience of last year, the team were very tired against Chelsea in that next game after losing in Munich,” he said. “All four [European] semi-finalists lost this weekend too and there are statistic that tell you the European games do take it out of you.

“Chelsea is massive, so I have to pick the right team [tonight] to ensure I have the same kind of freshness I need for Sunday. Hopefully I’ll have the nucleus of a team that’s still good enough to win.”

Ferguson is expected to rest Wayne Rooney tonight after he complained of a tight hamstring yesterday, while Rio Ferdinand might also sit the game out.

“I hope Manchester United don't get complacent [against Schalke],” he said. “Our work ethic will be very high in order for us to qualify.”