Jack Grealish is said to have been involved in a 'physical altercation' with Atletico Madrid defender Stefan Savic in the tunnel following Man City's progression to the UEFA Champions League semi-finals.
The incident occurred following a fiery game at the Wanda Metropolitano. Tempers boiled over at the end of the quarter-final second leg, with Felipe seeing red.
Grealish - an unused sub on the night - had had an altercation with Savic during the incident in which Felipe was sent off, with footage showing the the defender had pulled Grealish's hair on the touchline after the pair exchanged words.
The animosity between the two then continued after the full-time whistle, as BT Sport reported that the two were involved in a scuffle in the tunnel and eight police were tasked with intervening.
Atletico Madrid full-back Sime Vrsaljko was also part of the ruckus. Footage which has emerged shows the defender throwing an object at the Man City backroom staff in the tunnel.
Speaking after the game, Man City's John Stones was keen to focus on the football on the night, stating: "We know that they sometimes try and make things happen like that and we dealt with it really well.
"It is not nice to talk about and I don't want to dwell on it because over the two legs we played incredible against such an experienced side in what they do, we kept our tempers and it is easy to get drawn into stuff like that.
"We knew it was not an easy place to come, it is a hostile environment, it was a difficult night all round and how we defended and controlled ourselves over the two legs was incredible.
"Phil [Foden] was such a threat in both games, instant impact in the first and how he drove us up the pitch tonight, gained yards and free-kicks - I think he is feeling it now."