Goals from Sergio Aguero and two from Edin Dzeko turned things around for the visitors after Ross Barkley's wonder-strike early on. Although the visitors endured a difficult time after Romelu Lukaku pulled a goal back with 25 minutes to go they held on to assume pole position in the title race.
"I think it was a very big test. Three points is huge for us to continue to win the title," he said.
"It is important but we have not finished yet. We just have to won one of the three games we must win to lift the title.
"Maybe there was some doubt before the match about what Everton would do against us but we knew we would have to have a game against a very good team.
"This is a difficult place to come, especially when you concede a goal at the start, and we did well to come back.
"It was all about the concentration and character of the team today."