Sane starred in City's pre-season demolition of Hong Kong Premier League champions Kitchee on Wednesday, scoring twice in a 6-1 win.
Niko Kovac had labelled Sane as Bayern's "dream player" following the Bundesliga champions' 1-0 victory over AC Milan in the United States, as the saga rumbles on into the closing stages of the window.
Sane is yet to sign a new contract at City, though Guardiola has maintained the club wish to keep the former Schalke forward, who has been offered a new deal.
And, having been thrilled with Sane's display, Guardiola reaffirmed his wish for the 23-year-old to remain at City, though acknowledged it could be out of the club's control.
"He had a good game, especially in the second half," Guardiola told a press conference.
"He is a guy we appreciate, I like him a lot. I think he can be better. Two times, three times I have said that we want him to stay.
"That's why he has an offer to extend his contract. It's not in our hands.
"The agreement is good and if he wants to leave, I'll be sad. Hopefully, he stays."