Manchester - Lionel Messi was reportedly involved in an altercation with a Manchester City player after their Champions League game.
An unnamed player allegedly said something to Messi as they left the field following Barcelona's defeat to City.
Spanish newspapers said Messi responded by calling the player "stupid."
The papers said Messi tried to go to the City dressing room to pursue the matter, but was convinced not to do so by his Argentinian team-mate Sergio Aguero.
Messi scored the opening goal for Barca, but City returned through Ilkay Gundogan, who netted twice, before Kevin De Bruyne sealed a 3-1 win.
It was not the first time a Barcelona player has become frustrated with an opponent after a game this week.
Neymar pushed an opponent down some stairs at Camp Nou following their 1-0 win over Granada on Saturday, an incident that was caught on camera.
Meanwhile, City coach Pep Guardiola urged his team to build on what he felt should set the benchmark for future Champions League ties.
The Catalans thrashed City 4-0 two weeks ago with Guardiola highlighting the gulf in history between the two teams in the European competition. However, the former Bayern Munich mentor said that last night's victory would give the Sky Blues confidence in future fixtures.