Sport's top court, The Court of Arbitration for Sport (CAS), on Tuesday rejected French boxer Mourad Aliev's appeal over his Tokyo Olympics disqualification for headbutting his opponent Frazer Clarke of Great Britain.

The court said there may have been "the possibility of a technical error by the referee" but since the decision was taken during the fight it would stand.

Aliev had lodged a furious protest with an hour-long ring-side sit-in on Sunday after being disqualified in his super heavyweight quarter-final bout against the Briton following a series of headbutts that had injured his opponent.

Although the CAS panel did not rule out the possibility of a technical error by the referee, it said it "eventually decided to confirm the challenged decisions in view of the fact that the referee's decision to disqualify Mourad Aliev took place on the field of play."

Aliev's post-bout behavior had caused a furor, with the 26-year-old spitting out his mouth guard, punching a TV camera and making offensive gestures.

His opponent had suffered cuts above both eyes and was bleeding when the referee deemed an intentional headbutt by Aliev, winning the match with four seconds left in the second round.

Clarke is fighting Uzbeki Bakhodir Jalolov in Wednesday's semifinal.