Danny Garcia-Lucas Matthysse set

When pound-for-pound king Floyd Mayweather Jr. and Saul "Canelo" Alvarez signed in May to meet in a junior middleweight unification bout on Sept. 14 at the MGM Grand in Las Vegas, it was instantly the most anticipated fight of the year and a pay-per-view blockbuster-in-waiting.

Tens of thousands of fans turned out across the country to see the fighters during their recently completed 10-city media tour to promote the Showtime PPV fight, and tickets sold out in less than 24 hours to set a gate record of more than $19.5 million. Golden Boy Promotions chief executive Richard Schaefer said other revenue streams for the fight -- closed circuit, foreign television rights and sponsorships -- are also setting records.

But as huge as the fight is, the show got even bigger -- much bigger -- on Thursday, when Schaefer and Mayweather Promotions CEO Leonard Ellerbe announced on a media teleconference that the much-anticipated fight between unified junior welterweight titlist Danny Garcia and powerful interim titlist Lucas Matthysse has been added as the card's co-feature.

The fight, an expected action affair that will crown the clear No. 1 fighter at 140 pounds, is so significant that, even as an undercard fight, Schaefer announced that there would be a three-stop media tour -- New York, Puerto Rico and Los Angeles -- in support of the bout.

"To get these kinds of fights done is not so easy," Schaefer said. "I'm glad in the end it worked out. The fight fans will get a special treat.

"These people who wrote Danny was scared of Matthysse have egg on their face. He wanted the fight more than any other fight. I am really pleased this is happening. I was asked everywhere I went, 'Will you be able to pull it off, Garcia-Matthysse?' Well, yes, we did."

Mayweather-Alvarez is already expected to be a massive commercial success, but by adding another A-plus-level fight to the card, it becomes one of the best pay-per-views in history.

Schaefer said he believes that it could challenge the pay-per-view record of 2.5 million buys set by Mayweather's 2007 fight with Oscar De La Hoya.

"This is a huge visibility event, so as the leading promoters in the sport, we want to take on the responsibility of making new fans," Schaefer said. "This is the kind of event you are going to see non-boxing fans, people who have never seen a boxing match before, buying that night, and I think we want to take advantage of that and not only deliver them a great main course, but stellar appetizers.

"I want people, when they turn off their TV, to say, 'Wow, that was amazing, and I can't wait to see another boxing match.'"

Although the purses for Garcia-Matthysse were not disclosed, both will be seven figures, making it one of the most expensive, if not the most expensive, undercard fights in history.

"There was not much of a debate or issues with the fighters, but it's the most expensive fight ever put on a pay-per-view, so that took a lot of maneuvering and negotiations and a lot of money to get it done," Schaefer said. "And that really was the main reason it took so long.

"Of course, Floyd had to approve it because he's the overall captain of the ship, but it was up to us to find additional revenue sources, being from sponsors or foreign television sales, so some of the cost could be carried by other revenue sources."

Garcia (26-0, 16 KOs), 25, of Philadelphia, won a vacant title in March 2012 by dropping and outpointing Mexican legend Erik Morales -- who had been stripped of the title the previous day for failing to make weight -- and has made three title defenses. After beating Morales, Garcia knocked out Amir Khan in the fourth round to unify two titles in an upset. Then he drilled Morales in the fourth round in a contractually obligated rematch and survived a tough April 27 fight with former titlist Zab Judah to win a decision.

Three weeks later, Garcia was ringside in Atlantic City, N.J., on May 18 to see Matthysse (34-2, 32 KOs), 30, of Argentina, destroy titleholder Lamont Peterson in the third round of their non-title bout. Going into the Garcia-Judah and Matthysse-Peterson fights, Schaefer hoped to match the winners of the two fights in something of an unofficial tournament to crown the top junior welterweight.

"This is the fight I wanted and the fight that I asked for," Garcia said. "That is why I'm so happy this fight has been made and will be a part of this huge event. I'm more confident than ever in my abilities, and I'm going to show it on Sept. 14. Matthysse is a good fighter and has a big punch, but I'm a talented fighter with what it takes to be a champion and stay that way. This is an opportunity for the world to see what I can really do in the ring."

Said Matthysse, "I'm glad I finally get a chance to fight Danny Garcia. This is the fight that the entire boxing world, especially my country Argentina, and I wanted. I want to thank my promoters Golden Boy Promotions and Mario Arano for making this fight possible. On Sept. 14, I will show the world that I am the best 140-pound fighter on the planet."

Ellerbe said Mayweather, who controls the purse strings for his events, wanted to beef up the card.

"Floyd is trying to bring the awareness to the sport and give this fight the worldwide platform it deserves," Ellerbe said. "This is a tremendous fight. You have Lucas Matthysse, who is running everyone out the ring and who a lot of guys don't want to fight, and Danny Garcia stepped up and said, 'I want to be the guy to beat him.' Matthysse has tremendous punching power, but Garcia can punch with either hand. We want people to leave away from watching this whole card and want to see the next card we put on. ... This is Floyd trying to make boxing a mainstream sport."

Mayweather could also have ulterior motives. The winner looms as a strong candidate to be his next opponent, so having a big audience become familiar with Garcia and Matthysse makes sense. Mayweather also holds a welterweight title and likely will return to that division after the Alvarez fight. The Garcia-Matthysse winner, meanwhile, will have accomplished all he can do at 140 pounds and likely would move up to 147.

"Our focus is just on Sept. 14," Ellerbe said. "There are a number of guys who want to fight Floyd from 140 to 154. There are a lot of guys in the Mayweather sweepstakes."

Adding the fight to the card would have been impossible without Al Haymon, a powerful adviser who counts Mayweather, Garcia and Matthysse as part of his all-star roster. It is only recently that Haymon has shown a willingness to match his fighters. Schaefer said he was on board with the fight from the outset.

"Al Haymon is a huge boxing fan, and he believes in the best fighting the best," Schaefer said. "He has never been a stumbling block to the fight happening."

Schaefer and Showtime initially planned to schedule the fight for Sept. 7 as a regular Showtime main event. But issues finding a venue on that date and the carrot of creating such massive buzz with the public by putting it on the Mayweather-Alvarez card was too enticing.

"My first choice all along was to try to find a way to put it on Sept. 14," Schaefer said. "It would have been much easier to put it on a separate date and for us, as a promoter, it would have would have been more lucrative. But this is for the fans. I believe the exposure this fight is getting worldwide, with record numbers everywhere, that Danny Garcia and Lucas Matthysse deserve the kind of attention they will get by being on this card."

Schaefer and Ellerbe took several shots at promotional rival Top Rank on the call while lavishing praise on their own work.

"We didn't need to do this. Tickets are sold out. This is without question a thank-you to the fight fans and an attempt to bring new fans to the sport. Loaded pay-per-view cards are the hallmark of Golden Boy and Mayweather Promotions pay-per-views. The Butterbean days are over," Schaefer said in a shot at Top Rank, which used to feature the circuslike fights of the former toughman heavyweight on its pay-per-views. "This sets us apart from our competition."