The Germany midfielder sealed a 3-1 win 11 minutes from time after Callum Wilson cancelled out a lead earned for the hosts by Bernardo Silva and restored by Raheem Sterling.
As in the midweek 2-2 draw against Lyon in the Champions League, where Pep Guardiola's men twice game back from behind, Gundogan felt his team-mates responded well when their character was called upon.
"We tried to play better because we started quite well in the beginning, moved the ball very quickly and scored," he said.
"After 25 minutes we stopped a little bit, played too sloppy and missed easy, simple balls.
"We conceded the ball and were very defensive in that situation, couldn't press for the cross. Then it was a good header.
"It was not easy or usual to go in at half-time with a draw.
"It shows that the Premier League is a very tough competition and we have to struggle. You have to learn how to behave in these kind of moments when you are not able to control the game 100 per cent.
"The more we struggle now and the more we have to come through these kind of games will help us for the future.
"It was a tough game and a good result."
Gundogan has been the victim of serious knee injuries during his career, including cruciate ligament damage that decimated his maiden season at the Etihad Stadium in 2016-17.
He sat out the game in Lyon after only recently returning from a hamstring strain and the 28-year-old hopes to put such niggling problems behind him.
"It's always nice to score a goal in that situation. Leroy [Sane] made it quite simple for me," he said.
"It's all about getting another 90 minutes because in the last few weeks I suffered with different kinds of injuries.
"One week it was the foot, the next week it was the knee and then the hamstring. It's difficult with these kind of situations and I want to come back to 100 per cent as soon as possible."