LAS VEGAS >> They’re doing it again because the money is good, and the fight should be even better. The last time Brandon Rios and Mike Alvarado got in the ring together they stole the show, and this time they play starring roles.

Two old-fashioned fighters not afraid to take a punch to land one of their own. Two warriors too proud to back off an inch.

It’s a fight fan’s fight, just five months after they nearly knocked each other senseless in Southern California.

“It’s never too soon to do it again,” Rios said. “We are warriors and if you are a warrior, you want to fight again and again and again.”

Both junior welterweights were undefeated when they met in October on the undercard of a Nonito Donaire fight at the Home Depot Center in Carson, Calif. Alvarado would suffer his first loss, but not before almost stopping Rios in a slugfest that would have been fight of the year had Juan Manuel Marquez not knocked out Manny Pacquiao a few weeks later.

Instead of looking for a softer touch, they’re going to fight again Saturday night at the Mandalay Bay hotel-casino. Both say they know what to expect.

“Mike Alvarado is Mike Alvarado and Brandon Rios is Brandon Rios,” Rios said. “We are going to give the fans what they want, and we are going to give them a good show.”

Styles make fights, which makes Rios-Alvarado II so intriguing. Both fighters were happy to go toe-to-toe in their first fight — won by Rios in the seventh round — and both are happy to do it again.

“You can always train differently to try to change things up. But I think our styles and the way we approach the ring, it is automatically going to turn into that kind of fight,” Alvarado (33-1, 23 KOs) said. “They are the styles we have. We are both warriors. We just fight and whoever comes out on top, that’s just the way it’s going to go.”

That the rematch is happening so quickly isn’t just because the first fight was such a wild affair. Coming off the win, Rios was supposed to get a shot at Pacquiao, but those plans were cancelled when Pacquiao was knocked out by Marquez.

So HBO came up with some more money, and promoter Bob Arum asked them to do it again.

“I don’t usually like to do immediate rematches, but this first fight was really so great,” Arum said. “There was a demand for it to get done and the people at HBO came up with a financial package that was very appealing. Both fighters are getting considerably more than they got the first time. It’s the exception that proves the rule.”

Both fighters are brawlers, and both can hit. They fought a frenetic first round the last time out and pounded away at each other for nearly six more rounds before the referee stopped the fight with Alvarado backed against the ropes and taking punishment.

Rios (31-0-1, 22 KOs) threw fewer punches than Alvarado, but landed a bigger percentage. Unbelievably, neither fighter went down, even as they landed devastating blows to the head.

“Everyone kind of has a game plan when they go into a fight,” Alvarado said. “I knew it was going to turn into that kind of fight and I had prepared for a war. And that’s the kind of fight it ended up being.”

Though there is no real title at stake, the fight is scheduled for 12 rounds. Based on the first fight, though, few think it will go that long.

“We have the same type of style. We both go fight each other,” Rios said. “We try to get the job done the only way we know how.”