"They will say it's a good goal but from our point of view it is poor - the build-up to it and on the back post," the 35-year-old is quoted as saying by Wales Online. "Angel has to do much better and be stronger than that. He's got to be willing to get hurt, that's what you have to do on the back post.
"You know it's coming and he had time to think, it's not as if it's a split-second. We'd been working all week on those situations and that's the really disappointing part for myself.
"It's really disappointing because we talked about consistency all week and how the best teams in the best leagues consistently perform. To be good players you have to be consistent and unfortunately too many times this season we've been inconsistent."
The defeat leaves Swansea six points clear of the Premier League relegation zone.