Conor McGregor is about to beaten by Floyd Mayweather again -- this time in the race to become the world's highest-paid athlete

Conor McGregorGetty ImagesConor McGregor takes a shot of Notorious whiskey.

Conor McGregor’s dream of topping the Forbes rich-list of highest-paid athletes is probably going to be foiled by a familiar foe.

The Irish UFC star said last month that he wanted to dethrone Real Madrid footballer Cristiano Ronaldo at the top to the Forbes list.

A reported $US100 million (£77 million) payday for going 10 rounds with Floyd Mayweather on Saturday will mean he goes some way to achieving this.

But just as Mayweather triumphed in the ring, his earning power will also probably put him at the top of the money tree.

Mayweather banked a guaranteed $US100 million ‘purse’ for last Saturday’s Las Vegas showdown, while he could earn a further $US200 million from pay-per-view revenue.

To match Mayweather’s $US300 million earnings, McGregor would have to line up some more mega fights before next June, when Forbes publishes its annual athlete rich list.

His biggest UFC pay-day to date was $US3 million for his 2016 battle with Nate Diaz, according to MMA Weekly. He would have to take part in 67 more of these fights to achieve parity with Mayweather.

It means McGregor may have to settle for number two, which is still a significant improvement on his current placing of 24th. Ronaldo topped this year’s ranking after taking home $US93 million (£72 million), according to Forbes.

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