[2] The world's two top middleweights had collided the previous September and had fought a high quality contest that ended with a controversial split draw after the full 12 rounds.

On September 19, Golden Boy Promotions president Eric Gomez told ESPN that everyone on their side was interested in the rematch and they would hold discussions with Tom Loeffler in the next coming days.

Golden Boy president Eric Gomez told ESPN, "Regardless of if they did or didn't order the rematch, we are going to try to make it happen.

It was believed that Golden Boy would wait until after David Lemieux and Billy Joe Saunders fought for the latter's WBO title on December 16, 2017, before making a decision.

[13] On December 20, Eric Gomez announced that the negotiations were close to being finalized after Álvarez gave Golden Boy the go-ahead to write up the contracts.

[14] On January 29, 2018 HBO finally announced the rematch would take place on May 5 on the Cinco de Mayo weekend.

[17][18] The venue for the rematch was not confirmed until February 22, Madison Square Garden in New York City had been in the running to host the event, but it was eventually decided that the stage would be the same as the first fight, the T-Mobile Arena in Las Vegas.

[21] The fate of the rematch was put in jeopardy on March 5, 2018, when Álvarez failed two random urine tests, collected on February 17 and 20, for the banned substance clenbuterol.

[22] The Nevada Athletic Commission (NAC) opened an investigation,[23] and Álvarez was temporarily suspended on March 23, 2018—pending a hearing on April 10.

[25] Former two-time light middleweight champion Demetrius Andrade made an offer to fight if Álvarez received a long-term suspension,[26] as well as IBF #1 contender Sergiy Derevyanchenko.

[27] The next day, NAC chief Bob Bennett filed a formal doping complaint against Álvarez, which delayed the disciplinary hearing to the commission's next monthly meeting on April 18.

ESPN.com writer Dan Rafael felt that this delay made it more uncertain that the fight would go ahead, while T-Mobile Arena had already announced the previous day that it would offer full refunds on tickets.

Gomez explained that "given the current regulations in Nevada, we have been advised, and it is unfortunate, that Canelo won't be cleared to fight in May.

Although Golovkin stated the rematch had a 10% chance of happening, Eric Gomez and Tom Loeffler agreed to meet and start negotiating after May 5.

[40] On June 12, Golden Boy gave Golovkin a 24-hour deadline to accept a 57½–42½ split in Álvarez's favor or they would explore other fights.

At the same time, Loeffler was working closely with Frank Warren to match Saunders with Golovkin for the end of August.

[41] On June 13, 2018, it was announced that Álvarez and Golovkin had finalized a deal to hold the rematch September 15, 2018, at T-Mobile Arena.

[44] Álvarez started training for the bout on June 14 and stated his intention to apply for his boxing license on August 18.

[46] On September 3, due to a majority vote of the panel, the vacant Ring magazine middleweight title would be contested for in the bout.

Doug Fischer wrote, "We posed the question to the Ratings Panel, which, in a landslide, voted in favor of the magazine's 160-pound championship being up for grabs when the two stars clash at the T-Mobile Arena in Las Vegas.

For the WBO junior middleweight title fight, Brandon Cook weighed 153.2 pounds and Jaime Munguia came in at the 154-pound limit.

[49] Guaranteed base purses In front of a sell out crowd of 21,965, the fight was again not without controversy as Álvarez defeated Golovkin via majority decision after 12 rounds.

Golovkin, known for his relentless pressure and power punching, tried to control the pace of the fight but found himself unable to dominate Canelo as he did in their first encounter.

Canelo would win the next 2 rounds on each scorecard, landing the harder more explosive shots to the body and head while being aggressive, on the other hand, Golovkin still had not established his jab yet and was on the running side.

Golovkin did not take part in the post fight interview and made his way backstage where he received stitches for a cut over his right eye.