Manchester United midfielder Sir Alex Ferguson has apologised to supporters after defeat by Crystal Palace in the Carling Cup.
After Federico Macheda's penalty had cancelled out Darren Ambrose's stunning opener, Glenn Murray's extra-time header sent the Championship side through to the last-four.
Despite Murray appearing to be offside prior to his headed winner, Ferguson takes nothing away from a spirited Palace display.
"I don't know where to start to be honest," said Ferguson. "My apologies are to the fans because that was not a Manchester United performance.
"I don't want to take anything away from Crystal Palace," he added. "I am just very disappointed."
"I wish them every success and hope they get to the final because it was a fantastic, mammoth effort from them tonight.
"Every one of their players worked their socks off to try to get to the semi-final."
"Obviously the goal was offside - the second goal - from what I have seen," he added.
"We are not getting any luck from linesmen just now but I can't take that away from Crystal Palace. They fought hard to get the result and they deserve it."
Ferguson opted to keep faith with the same youngsters that had helped United overcome trips to Leeds United and Aldershot Town, with the likes of Macheda and Mame Biram Diouf preferred up front.
But rather than play with youthful exuberance from the off, the Barclays Premier League champions were frustrated by a hard-working Palace side.
Dougie Freedman's side will face fellow Championship side Cardiff City in the two-legged semi-final, with Manchester City and Liverpool facing off in the other last-four encounter.