Jessie Vargas has claimed that Conor McGregor was knocked out in a sparring session as he trained ahead of his fight against Floyd Mayweather.

Former two-weight world champion Vargas claimed that McGregor was knocked out during a sparring session with MMA fighter Bradley Wheeler.

Vargas said that Wheeler was brought in to help McGregor prepare for his first professional boxing fight but the decision backfired.

Conor McGregor gestures to the crowd as he promotes his fight against Floyd Mayweather

'I heard that they tried Bradley Wheeler but he knocked him out', Vargas told Villainfy Media.

Vargas added that he was confident of a Mayweather victory in the fight and was considering placing a bet on the American knocking out McGregor.

'I'm looking forward to Floyd coming out with a victory by knockout in six, seven rounds,' he added. 'I have no doubt. I actually wanna put some money on it. It's a 99 per cent win.'

Jessie Vargas said he had 'no doubt' that Mayweather would beat McGregor in Las Vegas

McGregor and Mayweather have just concluded their four-day promotional tour in the build up to their fight.

The pair squared up to each other in a heated exchange at Wembley on Friday night with McGregor referring to Mayweather as a 'stupid, baldy t***'.

The bout will be McGregor's first as a boxer in contrast to the experienced Mayweather, who holds an undefeated 49-0 record.

McGregor's camp denied Vargas' claim on Tuesday and said that he was referring to Brandon Rios rather than Wheeler, adding that neither fighters have previously trained with McGregor.