Sane has struggled to nail down a starting berth over recent months, with Guardiola preferring Silva and Raheem Sterling in his first-choice front three either side of Sergio Aguero.
But he was delighted by a game-breaking performance from the former Schalke star, who was introduced in a 51st-minute reshuffle after Fernandinho's excellent tackle on Paul Pogba compounded the Brazil midfielder's fitness struggles.
"I am so demanding of him and sometimes I like to be critical of him.
"We know his potential and we want to help him to be more consistent in his game.
"Not just in his actions with the ball, without too, and today he was so good and played at a high level."
The relentless nature of the title race means City could finish on 98 points, ahead of a Liverpool side on 97 – a total that would be the third highest in Premier League history.
Ahead of Sunday's trip to Burnley, Guardiola believes his players have to operate under that assumption.
"It's in our hands. Three games. We won the last 11, 18 of 19. It is incredible what these players have done so far but still we have a job to do," he added.
"If that victory happens in November and December, we can enjoy it more. Maybe tonight you can enjoy it but it's over, it's gone.
"You have to be focused. I know the people are going to talk about how beautiful and handsome we are, but now we have to go to Burnley and Burnley is always a tough, tough game to play.
"But we are fortunate that it is in our hands. Win three games and are champions."