BARCELONA • Barcelona star Lionel Messi was spat at by a River Plate fan during an ugly airport altercation following his side's 3-0 victory in the Club World Cup final in Japan, Spanish media reported.

Messi reportedly retaliated with a punch after being subjected to a series of insults from fans of the Argentinian club, as he was preparing to board a flight home from Tokyo's Narita Airport.

Spanish sports daily AS reported: "When Barcelona players were getting ready to go through passport control and security, several River fans insulted Messi and the issue escalated to the point that one of them spat at Messi."

According to several reports, an irate Messi responded by "punching" the fan who spat at him, before Barcelona coach Luis Enrique and team-mates Javier Mascherano and Luis Suarez stepped in to defuse the situation.

However, Catalan daily Mundo Deportivo explained that shortly after the incident Messi was seen to be smiling and relaxed, playing down the significance of the event.

Madrid-based daily Marca added that the group of supporters were also heckling former River player Mascherano, criticising him for "forgetting" his roots, with Mascherano having come through the youth ranks at the Buenos Aires club before making his professional debut with them in 2003.

River Plate have apologised for the behaviour of their fans.

"In relation to the attacks on Lionel Messi at Narita Airport, Club Atletico River Plate condemn all forms of violence and wish to apologise to the player and FC Barcelona," a statement read.

"River Plate congratulate Barcelona on winning the 2015 Club World Cup, held in Japan."

Messi scored the opening goal before two more from Luis Suarez. But the Argentina international has often been criticised for failing to replicate his Barcelona form for the national team.

River Plate president Rodolfo D'Onofrio was similarly critical of the behaviour of his club's fans.

"There's always one idiot, to use a more polite way of describing these people," he told Fox Sports Show.

"I've only just read that Messi was given problems by a fan at the airport who had drank more than he should have, and did something stupid against Messi.

"Messi is the best player in Argentinian football, he's a gentleman."

AGENCE FRANCE-PRESSE, THE GUARDIAN