United will have to come from behind to book a place at Wembley in the Carling Cup final after slipping to a shock 1-0 defeat away at Derby County.

The Reds endured an uncomfortable evening at Pride Park in the semi-final first leg clash and lost out to a fine first-half strike from the impressive Kris Commons.

Sir Alex made five changes to the side that had overcome Southampton in the FA Cup, with the weekend visit of Chelsea no doubt very much in his thoughts. Edwin van der Sar, Gary Neville and Dimitar Berbatov were all given the night off, while Michael Carrick and Ryan Giggs were handed places on the bench. Tomasz Kuszczak took over between the sticks, with Paul Scholes, Carlos Tevez, Rafael and Darron Gibson filling the other vacant posts. Eighteen-year-old striker Danny Welbeck, who opened the scoring at St. Mary’s, retained his place in attack.

Derby, meanwhile, had a new manager - Nigel Clough - to impress and with that in mind set about their task with real energy and endeavour which had a significant effect on United’s rhythm throughout the 90 minutes.

After just six minutes Kuszczak was forced to make a point-blank save, albeit from a tight angle, from Steve Davies who, having seen his initial cross from the left pinball around the area, latched onto Rob Hulse’s hopeful ball back into the danger area and fired goalwards. He got a second bite of the cherry when Kuszczak’s block rebounded back into his path, but Reds skipper for the night Nemanja Vidic was on hand to clear the danger.

Soon after, Mile Sterjovski saw his low drive,