Barcelona forward Neymar appeared to confront a Manchester City fan at the full-time whistle of the Champions League clash at the Etihad Stadium.
Neymar was substituted in the 80th minute of the last-16 first-leg game, which Barca won 2-1, and footage posted on YouTube shows the 23-year-old apparently remonstrating with a section of City's support from the visiting dugout.
Once the full-time whistle was blown, the Brazilian then walked to the pitch side and looked to be in a heated discussion with one City supporter in particular, with stewards intervening to defuse the situation.
The Brazil captain was quoted by media in his homeland as saying after the match: "I was just playing with him. He began to curse me and I ended up giving him a wave. I can not say what he told me, no. My mother did not bring me up that way. What his mother did not give him, my mother gave me."
The footage may slightly sour an otherwise excellent night for the Spanish giants, who took a giant stride into the quarter-finals of the Champions League in Manchester.
Former Liverpool forward Luis Suarez scored twice on his return to England although City striker Sergio Aguero narrowed the deficit before Lionel Messi missed an injury-time penalty.
Messi's spot kick was saved by City keeper Joe Hart, and the Argentine headed the rebound wide. Luis Suarez, who scored both of Barcelona's goals in the win, addressed the miss following the game.
"Sometimes penalties are missed," he said. "We would have liked a bigger lead. In the first half we had a lot of chances, and we could have scored more goals. In the second half they began stronger, and the goal put them back in the game.
"But we know that Manchester City are a great team with a lot of potential, and that they could make it difficult for us. They reacted and it was difficult."