Di Santo is convinced his team-mates can take heart from the loss and use it to their advantage.
The striker, 24, said: "We should have won the game or at least got a point, but maybe we were unlucky. It was arguably our best performance of the season in the way we took the game to Manchester City.
"Everybody did their jobs really well and we know that if we play like that in the rest of our games, then we will be okay. City have lost once at home all season - against Manchester United - and we were unfortunate not to become the second.
"I'm confident if we can play like that again, though, we will be able to come away with positive results in our last few games."