Sane then started the game but was forced off within 13 minutes after falling awkwardly under a challenge from Trent Alexander-Arnold. However, after tests this week, the extent of Sane's injury was revealed, though no timetable for recovery has been set.
A partial tear of Sane's ACL was the diagnosis, with the German facing at least five months out of action.
Manchester City are yet to provide deals on the extent of the injury and Kicker have a theory about that today.
"Leroy will have surgery in the coming week".
The 23-year-old has been linked all summer long with a move to Bundesliga giants Bayern Munich, having fallen out-of-favour under Pep Guardiola during the second half of City's historic treble winning campaign.
Bayern have not kept their pursuit of the Man City winger quiet by any means after embarking on an intense charm offensive this summer to try and capture Sane, reports the Manchester Evening News.
Sane has two years left on his contract, which City were trying to get him to extend amid the Bayern interest.