The City boss said: "I think already about Watford as we don't have much time, but to start away in the Champions League with a good result (is positive) and I know we played really good.

"We created incredible chances and all the guys were fantastic. It's a good result to start – better than last season."

With Aymeric Laporte already sidelined, an injury to John Stones on the eve of the game left Nicolas Otamendi as City's only fit specialist centre-back.

Midfielder Fernandinho filled in impressively against Shakhtar but Guardiola admits other options will also need to be explored.

Youngster Eric Garcia, who was on the bench in Ukraine, is an alternative but Guardiola may try switching some other senior players around first.

He said: "I didn't have doubts he (Fernandinho) could do it and he's going to do it (again).

"But Nico is 31, Fernandinho is 34, and next alternative is 18. For three or four months I don't know what will happen.

"Both were incredible tonight but we need another solution – Rodri or Kyle (Walker) maybe – because they cannot play every game at their age. But Fernandinho can play in any position and that's why he's so important for us."

Guardiola also picked out Gundogan and Mahrez for praise.

Asked if Gundogan did not get enough credit for his performances, Guardiola said: "The important thing is the credit he has from all of us, he is an exceptional player. It was outstanding from Ilkay today."

He added of Mahrez, who set up Gundogan's goal as well as scoring himself: "It's a pleasure to watch him play football."

Shakhtar occasionally threatened City on the break but coach Luis Castro admitted they paid the price for failing to take their chances.

He said: "We knew how difficult this game would be. Our plan was not letting City develop their attacks through the centre and we also wanted to organise fast counters and take our chances.

"At 1-0 Junior Moraes had a chance for an equaliser but we missed it and in a few minutes City scored the second goal. When you are 2-0 down you feel a mountain on your shoulders, so it was very hard in the second half. The game was finished by the third goal."