The winger was at the heart of the three goals in four minutes that burst the home side's bubble, scoring one and having a big hand in the others.
It has been a mixed week for Johnson, having not made the bench for Sunday's win at Old Trafford and coming off in the first half against Villarreal a week ago, and he told City's website, "Those three quick goals changed the game, their heads dropped and then it was our game to lose. We kept playing but we probably took our foot off the gas in the second half, we could have pressed a bit more but we passed it and in the end saw the game out.
"I'm pleased to start and delighted to get a full game. Obviously I was disappointed with the last couple of matches, but that's part of football. It was good to get out there and show the manager I'm here and fighting for a regular place.
"The win at Old Trafford is just one win. We want to win every game we play, no matter who it is against. We play Wolves again on Saturday, so this was a good platform for whoever plays, and it will be difficult for them at our place."