Speaking to the media, Emery said: "In the second half their confidence was going down and ours was increasing. It was fantastic how the players responded to everything we had worked on before.
"We were defending too low in the first half and we had to get into a good position to try to stop them dominating the ball. We defended well all game but we played with more personality in the second half than we did in the first.
"In the first 30 minutes, Manchester City played fantastic. If they had scored in that period then maybe they would have recovered their confidence but the second half was completely different.
"We dominated, we scored and through those circumstances they (City) were feeling worse than in the first half, and then there was the result as well."