There have been some huge championship showdowns in the all-time rivalry between fighters from Puerto Rico and Mexico, but none might be as significant, or as good, as the one announced on Thursday.

After months of excruciating negotiations, the deal was finally finalized for middleweight world champion Miguel Cotto to defend the title against former unified junior middleweight titleholder Canelo Alvarez. They will meet in a much-anticipated fight on Nov. 21 (HBO PPV) at Mandalay Bay in Las Vegas, Jay Z's Roc Nation Sports -- Cotto's promoter -- and Alvarez promoter Golden Boy announced.

Miguel Cotto knocked out Daniel Geale in June, paving the way for an upcoming mega fight versus Canelo Alvarez in November. AP Photo/Frank Franklin II

"I will give the fans the fight they want to see," Cotto said. "As I have always said, during my whole career, I am here to fight the best names and the best fighters. This will be another chapter in my career, and I will be ready for him. Fans will enjoy a real fight, another classic battle in the Puerto Rico versus Mexico rivalry."

That rivalry, one of the most intense in boxing, has included some huge fights, including Salvador Sanchez-Wilfredo Gomez, Julio Cesar Chavez Sr.-Hector Camacho, Felix Trinidad-Oscar De La Hoya and Cotto's two rumbles with Antonio Margarito.

"Historically, mega fights are made because fans demand them," Alvarez said. "In this case, the fans have spoken out, longing for this fight, and it is my pleasure to say that it is finally happening.

"All fights at this level are very important, but this fight in particular has something more. It will hold a special place in history as part of the big rivalry between Mexico and Puerto Rico, and I promise all the fans that this is going to be an event that will not disappoint."

A multi-city promotional tour is being planned with details to soon be announced.

"The great rivalry between Mexico and Puerto Rico has a rich history in the sport of boxing. Classic fights like Julio Cesar 'J.C.' Chavez versus Hector 'Macho' Camacho and Wilfredo Gomez versus Salvador Sanchez are prime examples of the history of that great rivalry," Jose "Chepo" Reynoso, Alvarez's manager, said. "Cotto-Canelo will become part of that history, a fight that most likely will be the biggest fight to date [in the rivalry] due to the great popularity of both of the warriors. Fans demanded this fight and now have it."

Rather than fight at the middleweight limit of 160 pounds, they will meet at a catch-weight of 155 pounds, a weight that does not favor either man, as Cotto eyes his second successful defense.

Canelo Alvarez Tom Hogan/Hoganphotos/Golden Boy

Cotto weighed 155 pounds when he knocked out Sergio Martinez to win the middleweight championship and he weighed 153½ pounds when he knocked out Daniel Geale in his first defense. Alvarez has had his three previous fights -- wins over James Kirkland, Erislandy Lara and Alfredo Angulo -- contracted at 155 pounds.

When Cotto knocked out long-reigning champion Martinez in the 10th round in June 2014 to win the world title, he likely punched his ticket to the International Boxing Hall of Fame as he became the first Puerto Rican boxer to win world titles in four weight classes (middleweight, junior middleweight, welterweight and junior welterweight).

Cotto took nearly a year off before making his first defense on June 6, knocking out former titleholder Geale in the fourth round in spectacular fashion with Golden Boy executives at ringside knowing they already had a deal in principle for the Cotto-Alvarez showdown, provided Cotto won.

The 34-year-old Cotto (40-4, 33 KOs) -- seemingly rejuvenated under the tutelage of Hall of Fame trainer Freddie Roach, whom he has been with for his past three fights -- looked sensational in the victory, but it took more than two months for the sides to finalize the details, mainly because of the painstaking assessment of everything by Cotto's camp.

A month before Cotto's knockout of Geale, Roc Nation Sports executives were ringside at Minute Maid Park in Houston on May 9, as Alvarez (45-1-1, 32 KOs), 25, Mexico's most popular active fighter, scored a ferocious third-round knockout of Kirkland in a wild brawl to take care of his business of helping set the table for the big showdown with Cotto.

"Cotto versus Canelo is the biggest fight in boxing, period," said David Itskowitch, COO of Boxing of Roc Nation Sports. "Given the fighters' styles, it has all the makings of a can't-miss, all-action fight. Couple that with the popularity of both Miguel and Canelo, and you have a true mega fight that fans have been clamoring for and one that no sports fan should miss. Nov. 21 has all the makings of a fight that will go down in boxing history as one of the greats."

Earlier this year, Cotto and Alvarez were negotiating to meet in May, but when Cotto's team took too long to make up its mind on the deal, Alvarez walked away because he did not want to lose a May date and moved on to face Kirkland. It turned out that Cotto was in the process of leaving longtime promoter Top Rank, with whom his contract had expired, to sign a lavish deal with Roc Nation Sports, which then went to work on putting together the mega fight with Alvarez.

The Cotto and Alvarez pairing is a natural. They both have enormous fan bases, bring exciting and aggressive styles to the ring and are well-known for having been in major pay-per-view fights, including against pound-for-pound king Floyd Mayweather, who won decisions against both of them in two of the biggest-selling and most lucrative fights in history.

"This is the fight of the year that true boxing fans have been waiting for between two of the biggest stars in the sport today," Golden Boy CEO Oscar De La Hoya said. "Cotto versus Canelo will be an epic showdown, full of nonstop action from the moment the first bell rings. This fight is an example of exactly what Golden Boy Promotions does: puts on the best fights between top fighters."