First Silva's through-ball sent De Bruyne through and he squared for Sane to sweep past Forster, then Aguero nodded in his 11th goal in 11 games.
"I said to the players from the beginning we are going to play pre-season in China to play a friendly game and we have to win that game".
A City victory would be their 19th of the season, equalling their total number of Premier League wins in 2015-16 under Manuel Pellegrini.
"In recent games he has played he has delivered performances and hopefully he can stay fit".
"When something like this happens I feel like I'm giving something back to the team and the fans and that's what you see in those moments".
"That is why I am so, so glad for the fans we have because for the first time in my life I have experienced that".
Mid-table Saints failed to create many chances against a City side well marshalled by Kompany, with Dusan Tadic shooting over before the break.
Two soon became three following another De Bruyne assist, this time racing to the byline and floating the ball into a risky area for Aguero to power home his 11th goal in 11 outings.
Sane notched his ninth goal of the season following a tremendous display on the counter attack.
There is, however, a possibility that Guardiola could secure some silverware in his first campaign at the club in the form of the FA Cup, with a semi-final clash against Arsenal to come next week. He has the quality to move quicker, to find passes in small spaces, to help us in set pieces, both offensive and defensive because he's a real defender.
"This result is so important for our qualification for the Champions League". My feeling before was he was just waiting to score a goal.
They could register three Premier League wins in a row for the first time under Claude Puel.
A smart turn from Nathan Redmond opened up the City defence out wide for Gabbiadini, who returned following a three-game absence, but his cutback was sacked over the bar from Dusan Tadic. If you want to become a stronger club and a stronger team you can not drop points at home; because our quality is higher we can not drop points.