Moyes admitted his side could have been out of the game by the interval.
He said: "They bossed the game and we never laid a glove on them.
"We were fortunate to go in at half-time 1-0 down.
"We changed the system round a little bit at half-time and I don't know if it was the system but we got closer to people, looked more attacking and were a bigger threat.
"We set out to try to contain Man City but it is very difficult to contain David Silva.
"I think he is as good as anyone in the Premier League at the moment."