The victory saw Swans move out of the dropzone.
“It's a big sorry to the supporters who traveled through the snow to get here," admitted Moyes. "We let them down badly. We're massively disappointed with how we played and it was certainly the worst performance since I've been at West Ham and we just never looked at any time as if we were in control.
“For the first goal, we were passing it across the back, then passed it back to the goalie, it bobbled and went out for a throw-in, and from the throw-in we concede the first goal from something I think we should save.
“We then conceded two goals from corner kicks and one from a penalty kick, so from my point of view, they were all avoidable. I didn't think it was Swansea who opened us up or carved us open, but it was just generally a poor performance and poor all-round.
“We had a couple of half-chances in the second half and started the second half with more intensity, but the first time Swansea went up into our half, they got a corner and scored from it."