Lionel Messi was sent off before halftime and then angrily hit out at "corrupt" tournament organizers after Argentina beat Chile 2-1 to win a bad-tempered third-place playoff at the Copa America on Saturday.

It was the Barca star's second red card of his career as his only other red card was on his international debut 14 years ago.

On the 34th minute, Chilean captain Gary Medel shepherded out a ball near his own goal. Messi challenged him from behind and Medel reacted angrily, pushing the Argentine and raising his hands.

The Paraguayan referee showed Medel a red card and even though Messi did not react, he too was sent off, prompting boos in Sao Paulo's Corinthians arena.

Reports said the Barcelona forward did not attend the ceremony to receive his third-place medal and he later hit out at the South American soccer confederation (CONMEBOL).

"We don't have to be part of this corruption," Messi told reporters. "The lack of respect that they have showed us throughout this tournament.

The corruption and the referees, they don't allow people to enjoy soccer, Messi said.

"I think the cup is fixed for Brazil," Messi added. "I hope that the VAR and the referees have nothing to do in this final and that Peru can compete because they have the team to do so although I think it's difficult."

His comments came four days after Argentina were beaten 2-0 by arch rivals Brazil in a semifinal that was marked by a number of contentious refereeing decisions.

Argentina were furious that VAR was not consulted for two possible penalty decision, with the Argentine soccer association president writing an angry letter to CONMEBOL to express his disgust. 

Messi's frustration was evident in the mixed zone after what was only the second red card of his career.

"You saw what happened," he told reporters. "A yellow would have ended it for both of us. The important thing is that with 10 the team finished well and won."

The referee also showed six yellow cards in a match that was disrupted by 37 fouls.

Sergio Aguero put Argentina 1-0 ahead in 12 minutes and Paulo Dybala doubled it ten minutes later with a nice finish after Giovani Lo Celso put him through the goal.

Artur Vidal pulled one back for Chile from the penalty spot on the 14th minute into the second half.

Hosts Brazil face Peru in the final on Sunday in Rio de Janeiro.