Mayweather vs. McGregor: What's the big deal?

LAS VEGAS, Nev. (KARE) - Floyd Mayweather has weighed in at a trim 149 1/2 pounds for his boxing showdown with Conor McGregor, who also made weight at 153 pounds.

The undefeated boxer and the two-division UFC champion weighed in well below the 154-pound limit before a raucous crowd Friday at T-Mobile Arena, which will host their bout Saturday.

The enthusiastic included thousands of McGregor's vocal Irish fans, who sang and waved flags. Mayweather was the villain as usual, but his cheering section also appeared to be more robust than usual for the American antihero.

Mayweather had expressed doubt McGregor could make the weight.

Mayweather expressed no concern about his own weight disadvantage, saying, "Fighting wins fights."

If McGregor manages to knock out Mayweather, Las Vegas bookmakers will suffer the biggest single event loss in the history of sports betting.

McGregor fans are flooding casinos with small bets on the longshot mixed martial artist. He makes his pro boxing debut Saturday night against Mayweather, who is 49-0 and considered the best defensive fighter of his generation.

About 95 percent of the bets are on McGregor. Mayweather bets are much bigger - an average of $4,000 per bet to McGregor's $125 - but that isn't enough to cover the casinos' potential losses.

William Hill oddsmaker Nick Bogdanovich says his chain will suffer its worst lost ever if McGregor gets a knockout.