The Reds were missing eight established first-team players for various reasons but Ferguson refused to use that as an excuse.
"I can't have too many complaints," Sir Alex told Sky Sports.
"It's not the result we wanted. But given the changes I had to make, it's credible. We were the better team in terms of possession and pressure, but we didn't make it count in the second half."
"In the first half we played well," added the boss. "Their goalkeeper was fortunate when Fraizer Campbell's header hit him on the head. He made three or four good saves. They took the lead, but when we got the equaliser straight away I thought that would have sent us on our way."
Sir Alex continued: "Our attacking play was good in the first half. But in the second half, having lost Michael (Carrick) and then Ryan (Giggs) to injury, we lost a bit of experience at a vital moment in the game.
"Without the proper balance to the team in terms of width, it was a struggle in the second half for us. We couldn't break them down, although we hit the bar through Vidic, but nothing too dangerous."