Junior welterweight titleholders Terence Crawford and Viktor Postol, regarded as the two best 140-pound fighters in the world, will meet to unify their belts on July 23. The deal, in the works for the past few weeks, was finalized Monday with the Postol camp signing off.

Crawford signed his contract about two weeks ago. The fight will headline an HBO PPV card at the MGM Grand in Las Vegas and will include super middleweight world titleholder Gilberto "Zurdo" Ramirez making his first defense against Dominik Britsch in the co-feature.

Top Rank promoter Bob Arum would have preferred to make a deal with HBO for Crawford-Postol to be on the network, rather than pay-per-view, but HBO's budget issues prevented that from happening. Arum at least made a very attractive fight for big stakes.

"It's a very good matchup, the best you can make in the junior welterweight division," Arum told ESPN.com. "What it really is is a fight for supremacy in the division. I'm very pleased with it, and I think it will be a very competitive fight."

The fight will be the first on pay-per-view for either fighter. Arum said he would need to generate about 75,000 buys, at about $50 apiece, to break even on the event.

Crawford (28-0, 20 KOs), 28, of Omaha, Nebraska, the former lightweight champion and 2014 fighter of the year, moved up to junior welterweight and won a vacant world title by sixth-round knockout of Thomas Dulorme 13 months ago. He scored knockouts in his first two defenses, in the 10th round against mandatory challenger Dierry Jean in October and in the fifth round against Hank Lundy in February.

His third defense against Postol figures to be much more competitive and is the kind of significant fight Crawford has wanted.

"This is a great opportunity to show the world I'm the best champion at 140 pounds," Crawford said.

Cameron Dunkin, Crawford's co-manager, said he was pleased to get Crawford such a meaningful fight.

"This is a great fight, and Terence will prove he's not only the best 140-pound fighter in the world but that he is pound-for-pound the best fighter in the world," he said.

Viktor Postol (right) will make the first defense of the vacant title he won in October over Lucas Matthysse when he faces Terence Crawford in July. Jeff Gross/Getty Images

Said Brian McIntyre, Crawford's trainer and co-manager: "We are going to show the world how basic Postol really is and that he got very lucky against (Lucas) Matthysse."

Postol (28-0, 12 KOs), 32, of Ukraine, who is trained by Hall of Famer Freddie Roach, will be making the first defense of the vacant world title that he won in upset fashion by knocking out Argentine slugger Matthysse in the 10th round on Oct. 3 in Carson, California.

"I have asked for this fight for some time," Postol said. "I am very confident, and this will be a great fight for me. I want to thank my promoters, Elite Boxing and Top Rank, for making this fight a reality for the fans."

Vadim Kornilov, Postol's manager, said he believes the fight is about as even a matchup as one could ask for.

"This fight is pay-per-view view material because no one knows what to expect," Kornilov said. "Both guys are 28-0. Either one of these guys can win and go on to become the next star in the division. It's the type of fight fans don't get to see often these days."

Top Rank has scheduled a news conference to formally announce the fight on May 10 in Beverly Hills, California.

Ramirez (34-0, 24 KOs), 24, of Mexico, won a 168-pound world title by shutout decision against long-reigning titleholder Arthur Abraham on April 9 on the undercard of Manny Pacquiao-Timothy Bradley Jr. III, also at the MGM Grand.

Britsch (32-2-1, 11 KOs), 28, of Germany, who will be taking a big step up in competition, has won four fights in a row since an eight-round decision loss in 2014.

The other two bouts on the pay-per-view telecast are not finalized, but featherweight up-and-comer Oscar Valdez (19-0, 17 KOs), a two-time Mexican Olympian closing in on a mandatory world title shot, likely will be in one fight, Arum told ESPN.com.

Arum said Japanese middleweight Ryota Murata (9-0, 6 KOs), a 2012 Olympic gold medalist, will also be on the card, as long as he defeats Brazil's Felipe Santos Pedroso (13-1, 11 KOs) in a scheduled 10-round fight May 14 in Hong Kong and comes out of the bout healthy. Arum said it has not been determined whether Murata's fight will be part of the American pay-per-view telecast. The fight would be Murata's second in the United States. He fought in November in Las Vegas on the Bradley-Brandon Rios undercard.

Arum said another fight under consideration for the pay-per-view is a welterweight bout between Jose Benavidez Jr. (24-0, 16 KOs), a former interim junior welterweight titleholder, and Francisco Santana (24-4-1, 12 KOs).