The Latics boss was frustrated with Wilson''s opener which looked offside.
“We knew we were in for a tough test today in playing one of the best teams in the division and they’re a team that have already had eight away wins,” the Scot said.
“I thought first-half it was pretty even-steven until the goal and, having looked back, we’re disappointed because it’s offside as Yann Kermorgant flicks it on to Callum Wilson who is in an offside position.
“That’s an error and then that took the wind out of the sails a little bit before we give away a poor goal for their second as we give the ball away right on our own 18-yard line and allow a free shot on goal, you can’t do that against a good team.
“I thought second-half it was very much even-steven again but the boy Wilson managed to get away for their third and afterwards we came back into it again and had two or three chances ourselves but it’s fine lines and they’re a good team.”
The Latics travel to Nottingham Forest on Wednesday night and will be looking to close the seven point gap to safety.