United hit the woodwork twice and had a number of penalty claims turned down in their search for an equaliser.
Ferguson believes that their poor first-half display gave them too much to do as they entered the break 2-0 down, but praised his side's attitude in the second half.
"It was quite a game. The first half we never started, didn't get into the game," said Ferguson.
"From there we were just playing against the wind. The second half we played fantastic, just trying to get something from the game, and I think we were very unlucky.
"I think the attitude changed, that was the important thing. Wayne's (Rooney) ability does help but the attitude of the players was excellent everywhere on the pitch."
The result leaves United third in the Premier League table, level on points with rivals Manchester City.