Pep Guardiola has sent his best wishes to a Manchester City fan who is in a critical condition in hospital after being assaulted following the Champions League win at Schalke on Wednesday.
German police said the 32-year-old man had suffered a serious head injury in a violent confrontation with two Schalke supporters inside the Veltins Arena.
ESPN FC has been told that the supporter was in Germany with his family for the game, and that his father, mother and sister had remained behind.
"Yes we knew it the day after, of course it was terrible news," Guardiola told a news conference.
"A family -- a mother, father, sister. Unfortunately, it happened. Of course, our thoughts and best wishes from all of us to them.
"It was really tough news. Football is always a game, spectacular to everybody who enjoys it, but still right now this kind of thing can happen, unfortunately.
"Hopefully the police in Germany can solve the problem and the most important thing is the guy can recover and get well as soon as possible."
The supporter, who has not been named, has been placed in a medically-induced coma and City confirmed that staff had remained in Germany to support his family.
Gelsenkirchen police said in a statement on Thursday afternoon that the 32-year-old man was punched amid a brawl between two Schalke supporters and two City fans outside the away sector.
The man, who had travelled to Gelsenkirchen with three other members of his family, fell to the ground, with the fall resulting in a head injury.
In a statement released on Thursday, Greater Manchester Police said: "We are aware of an assault that occurred following the Schalke vs Manchester City fixture.
"We are working alongside the football clubs and German authorities to support their investigation and the man's family. "We would urge anyone with information to contact us on 101 or via live chat so we can share intelligence with our colleagues in Germany."
ESPN FC's Germany correspondent Stephan Uersfeld contributed to this report.