Mayweather, 40, is the clear favorite to win the bout, but he has been told not to underestimate his rival .
McGregor’s coach John Kavanagh said today that the UFC keeper is in the best shape of his life and destined to upset the American.
He tweeted: “I’ve been with Conor a while. This is the best bodily proviso I’ve seen him in. incomparable work ethic.”
though former boxer Ricky Hatton has promised his support to McGregor, he fears it could be a walkover for Mayweather.
“I feel unprepared to say this but I’d be very amazed if McGregor wins a round,” he admitted.
Mayweather is the bookies’ favorite going into the fight, with Bet fair giving him odds of 1/7.
McGregor remains the underdog at 5/1, according to Bet fair, with longer 6/1 odds to win by knockout.
Betfair spokesperson Katie Baylis said: “It’s now a month until one of the most expected fights in recent memory, and we have seen a phenomenal amount of money already bet, with £7.5m bet on the outcome alone.
“The maximal single bet was £100k on Mayweather Jr at the start of the month when his odds were around 1/5 and we expect to see plenty more bets of this temperament as we get closer to the fight.”
The fight is on track to become the biggest in betting history.
Latest odds (taken from Betfair at 5.00pm on July 27)
Mayweather win: 1/7
McGregor win: 5/1
How much will Mayweather and McGregor earn from the fight?
Mayweather is expected to pocket at least £78.5million ($100million) from the fight, while McGregor is thought to have agreed a smaller fee.
The Irishman will pocket £12million ($15million) less than his rival , according to UFC chairman Dana White.
But the purses are likely to increase further once bonuses and other add-ons are taken into account.
Mayweather took home in the region of £180million after he defeated Manny Pacquiao in 2015, according to Forbes.
What is Floyd Mayweather’s net worth?
The fight will take place on August 26 at the T-Mobile Arena in Las Vegas.