LA PAZ: A knee to the groin may not be quite Machiavelli, but it was no less effective for Evo Morales in asserting his presidential authority.

With one deft movement, Bolivia's combative leader felled an opponent in a football match against a team of political rivals. The receiving player crumpled in agony holding, as local media put it, his “testicular zone”.

The incident, during a match on Sunday to inaugurate a renovated stadium in the capital La Paz, was captured on video and aired on local TV stations on Monday night and uploaded on to YouTube.

The friendly match started when, wearing a No 10 green jersey, Morales, a football fanatic and Bolivia's first indigenous president, led his team of bodyguards and officials on to the artificial pitch.

The yellow team was led by Luis Revilla, mayor of La Paz and a political ally turned foe of the president. After smiles and handshakes the game began. Within five minutes Daniel Gustavo Cartagena, in the No 2 jersey for the mayor's team, scythed into the president after he passed the ball, gashing his right leg.

Morales, 50, a former Aymara llama herder and coca farmer, is not known for indulging critics, let alone people who foul him. He walked up to Cartagena, indicated his wound, then kneed him in the groin. The player collapsed, prompting audible whistles from spectators.

The match deteriorated into a bad-tempered contest. By the end, the match drawn at 4-4, two players from each side had been sent off, including Cartagena and one of the president's bodyguards.

One bodyguard tried to arrest Cartagena after the final whistle, the newspaper La Razon reported, but he was released after Revilla intervened.

Morales denied ordering the arrest but was unrepentant about his response to Cartagena's foul. “I passed the ball and suddenly I received a hammering. It's not the first time it happened.”

Revilla also played down the incident, saying: “This was a football game and on the field we are all players.” It was not clear if Cartagena was a member of the mayor's political party, Movement Without Fear.

A medical bulletin from the presidential palace said Morales received a laceration on the inside of the right leg. Dawn /The Guardian News Service