He described the feeling of scoring in such an important match as incredible, as the Gunners ran away 5-1 winners.
Havertz also credited the team’s hard work and the fantastic support from the fans for making the victory possible.
Post-game, he told Sky Sports: "I think we managed to press them quite well, we didn't give them much time. City are a top team and sometimes they beat the press but I think our energy was good, we used our chances and at the end I think it was a good game.
"I think its the timing, we train it a lot of times, it's not only us two, it's everyone when we push and go through the defensive players everyone needs to push through and the energy there is very important. We are the first to press, but the rest of the team are doing it excellently as well.
"I think I was a bit frustrated from the chance in the first half, so I thought to myself I need to score one and when I saw it go in I was very happy."