He told BBC Sport: "It is disappointing to go in front and then lose the game. I thought the performance was good, we dominated the game, particularly in the second half.
"Swansea were struggling to get out of their area but we couldn't get that second goal. They saw that out and got some luck with their goal. We created lots of chances but, in fairness, Swansea defended the box well. But we have to move on - it was one of those games.
"We certainly deserved to win the game. That's the disappointing thing, when you play well and can't get the win. But that's football."
The result leaves United fourth in the Premier League table.