The Gunners were beaten 3-1 by the Premier League champions at the Etihad.
Sergio Aguero netted a hat-trick for Pep Guardiola’s side with Laurent Koscielny scoring from a corner for Arsenal.
The defeat means Manchester United have leapfrogged Emery’s side as a result.
But the Spaniard was still happy with Torreira and Guendouzi.
Emery said: “I cannot say a lot about that. They showed their superiority at the end of the match.
“We lost some duels. We have some young players who are playing their first year in the Premier League and they can improve a lot.
“I’m very happy with Matteo Guendouzi and Lucas Torreira’s performances today, but they also need time to improve and to take confidence, to take experience for their future here.
“With the result, it’s not easy to say that, but there are some positives that we can look at from our players today.”
Torreira gave his own verdict on losing to the champions at the Etihad.
He explained: “Well it was a very difficult game to come up against one of the best sides in the Premier League.
“We knew that would be the case and there were times where we managed to stay in the game, we were sticking together and we pressed them.
“From there, we managed to get the equaliser in the first half.
“Then, because of things that happened in the game, they managed to get it to 2-1. Then in the second half it was a completely different game.
“We went looking for the equaliser. We couldn’t create the chances, they did, and they got the third goal.”
Arsenal return to action on Saturday when they travel to bottom of the table Huddersfield.