There was chanting throughout, echoing some of the street protests in Hong Kong in recent weeks, but the game passed off peacefully, aside from a late pitch invasion by one fan.
City were not distracted and Sane, whose future remains the subject of considerable speculation linking him with Bayern Munich, was in good touch.
The German netted City's second and fourth goals before the visitors' scoring was wrapped up by youngsters Nabil Touaizi and Iker Pozo. Law Tsz Chun scored the hosts' consolation.
City manager Pep Guardiola has been asked about Sane repeatedly throughout City's tour of Asia and he again reiterated his hope the winger stays after the match.
"He did a good game especially in the second half," said Guardiola. "He is a guy who I appreciate a lot.
"Again, I have said two or three times, we want him and we want him to stay. He has an offer waiting to extend the contract.
"It's not in our hands. He has to decide. If he wants and there is an agreement then it's good, but if he wants to leave he can do, but we will be sad. Hopefully he stays."
Guardiola said the protest chanting did not affect his players.
He said: "Sometimes this kind of thing happens in society. Hopefully they will solve it.
"But we were quite well. We moved from Hong Kong and the players had a day off and nothing happened. The game was normal."
The energy-sapping heat and humidity City have been playing in throughout their tour – which included two games in China last week and involves another match in Japan on Saturday – is alien to the English game.
All this has come after City's initial flight to China was also delayed by two days.
Yet Guardiola has no concerns about his side's preparations for the new campaign, which begins with the Community Shield against Liverpool on August 4.
The Spaniard said: "With situations I can't control, I adapt. We know we have to be here so we do training as best as possible.
"We were delayed and we could not fly, which was a pity, but we trained in Manchester and that was good for everybody.
"Great athletes, great teams never complain about what happens. We learn from them.
"We are not going to have a chance to win the Community Shield or a chance to win at West Ham if we say what a disaster about the humidity or conditions for training.
"It is what it is. It's not good but there are teams training in worse conditions than this.
"It is nice to be here and the players have done incredibly, off the pitch too.
"We have the Tokyo game then a week in Manchester to prepare for the Community Shield, and another week for the first Premier League game.
"I would have preferred another way but it is what it is."