Junior welterweights Brandon "Bam Bam" Rios and Mike Alvarado violently pounded each other with abandon in October, leaving each other bruised and battered in one of the most helacious fights in recent years. Now they are going to do it again, promoter Bob Arum told ESPN.com on Wednesday.

Arum said he finalized the rematch on Tuesday night. It will take place March 30 at Mandalay Bay in Las Vegas and headline an HBO broadcast.

"We got it done," Arum said. "We had to make the money work with HBO and (Tuesday) night it fell into place."

The fight will come five months after Rios stopped Alvarado in the seventh round of their thriller at the Home Depot Center in Carson, Calif. The first fight, an HBO undercard bout to the Nonito Donaire-Toshiaki Nishioka junior featherweight main event title fight, was a scheduled 10-round nontitle bout. The rematch, however, will be a 12-rounder for a vacant interim junior welterweight world title.

The first fight featured non-stop back-and-forth action, including in the unforgettable fifth round, until referee Pat Russell stepped in to stop it in the seventh round after Rios badly staggered Alvarado and had him defenseless on the ropes. At the time of the stoppage, two judges had the fight 57-57 while Rios led 58-56 on the third scorecard.

"I am ready for this fight again," an excited Rios told ESPN.com. "The first fight was awesome. We traded big punches and we landed big shots. This fight will be similar but I know better how to fight him now. I've been watching our fight over and over and over. I have a feeling that in this fight he will come back and try to outbox me from the outside. But I am ready for anything he brings, A to Z."

Rios said his name for the fight is "World War II."

"If he comes to fight me like he did the first time, this fight could be just like the first fight again," Rios said. "We're both hungry and we both possess power."

Some thought Russell's stoppage was a tad premature. Alvarado and his team certainly did. Rios said he wants to make sure there is no doubt this time.

"I think I'm going to knock him out again and I don't want the referee to stop it and have Alvarado saying the referee stopped it too soon," Rios said. "I want a 10-count knockout. I want the 10 count."

Even before the first fight, many were picking it as a can't-miss action fight and possible fight of the year. It lived up to all of the pre-fight hype. Now, expectations for the rematch will also be sky high.

"I think it's going to the be the same thing, like crazy," Arum said. "It was like watching a football game where this team is going to win and then you think the other team is going to win. The ebb and flow was so dramatic. Until Rios stopped Alvarado, I had it going back and forth for both of them. It was an amazing kind of fight because of the ebb and flow.

"This rematch won't be any different. That's how these two guys fight. The fans are in for a great treat."

Said Top Rank's Carl Moretti: "We think this is round eight, just a continuation of the first fight, which was the fight of the year (to many). I don't know what's going to change."

Rios was the likely next opponent for Manny Pacquiao this spring, but that was before Pacquiao got knocked out cold in the sixth round by Juan Manuel Marquez in December. With the fight down the drain, Top Rank and HBO began working on Rios-Alvarado II.

Rios (31-0-1, 23 KOs), 26, of Oxnard, Calif., said, of course, he would have liked to fight Pacquiao, a fight worth millions more to him than Alvarado. But he also said he wanted to fight Alvarado (33-1, 23 KOs), 32, of Denver, again. Even before it was made, Rios said he's been watching their fight repeatedly, and not just for scouting purposes.

"I loved the fight," Rios said. "I'm a fan and I love that fight. I watch it over and over like a fan every day. I couldn't believe I took some of those big shots and that he took the big shots I gave him. The fans, of course, they know I always fight my heart out for them."

Although the fight is for an interim belt, it very well could be for the full title by fight time. Marquez holds the WBO version of the 140-pound title, but has not defended it and fought Pacquiao at welterweight. Marquez's next fight is likely to be a fifth fight with Pacquiao, also at welterweight.

"Marquez will eventually be vacating (the title)," Arum said. "He could vacate by the time the (Rios-Alvarado) fight happens. It's up to him but I will talk to him before March 30."

Rios, a former lightweight titleholder, said that having a title, even an interim version, on the line gives him more motivation for the rematch.

"I want to become a world champion in two weight classes," Rios said. "So I know I'm more pumped up and even more focused having this belt (on the line). We'll be ready and I'm pretty sure he will be ready. I know he will come prepared. He will have a lot to prove because he wants that revenge and that title. I want that title. We both have something to prove and we'll both train our asses off."

Alvarado was not available for comment because he was in a training session.

Arum said a formal news conference is being planned to announce Rios-Alvarado II on Wednesday in Los Angeles.

As excited as most fight fans will be about the fight – and as much as the fighters wanted it – Cameron Dunkin, Rios' manager did not want the fight.

"It's a fight that I didn't want and I'll say it again on the record," Dunkin said. "I didn't want the first one either and when everyone started giving me credit for it, I said I didn't want it. I know how hard this fight is. I know how rough this fight is.

"You know how rematches are -- just because a guy wins the first one does not mean you win the second one. When the rematch came up, I talked to (Rios trainer) Robert (Garcia) and told him to make sure that Brandon knows this is going to be tougher than the first one and Robert said he already talked to Brandon about it and Brandon said he knew it was a tough fight and that he wouldn't take it lightly just because he won the first fight. This is the fight Brandon wants. He wants to leave no doubt in anyone's mind because some people were saying it was a quick stoppage. He said, 'No excuses this time. I'll do it again.'"