Golovkin-Canelo II is a grudge match of possibly historic proportions

The consequences of the Gennady Golovkin-Canelo Alvarez middleweight title fight Sept. 15 in Las Vegas are immense for each man.

Golovkin, a 36-year-old boxer from Kazakhstan, confided in a recent interview that he views this rematch with his bitter rival from Mexico as his defining bout, pointing to “time” as the leading reason.

“This is the biggest fight of my boxing career because of the time for me … maybe I won’t have a bigger chance in the next few years than I have right now,” Golovkin said. “He’s a huge name, this is a huge situation and I believe whoever wins is the pound-for-pound champion. So much attention, so many sponsors, so many people watching this fight — I like this.”

Alvarez, 28, has been stained by a six-month suspension that caused the cancellation of their May rematch after his two positive drug tests for the banned stamina-building substance clenbuterol. The two fought to a draw in September 2017.

Alvarez (49-1-2), a former two-division champion who claims he accidentally ingested the substance by eating contaminated Mexican beef, is presented the opportunity for vindication after producing a series of clean drug tests from the time this bout was announced.

“Never in my life have I felt the way I feel today,” Alvarez said of wanting to finish Golovkin (38-0-1). “I’m very motivated and confident about all that’s been said to get in the ring to hurt him.”

Golovkin-Alvarez II on HBO pay-per-view has the potential to stand as the most lucrative championship boxing match since Floyd Mayweather Jr.-Manny Pacquiao in 2015, which drew 4.4 million viewers and generated $400 million.

This grudge match has brought each man to emphasize their interest in winning by knockout, and a convincing loss by either could mark a plunge in popularity.

“The fact Canelo has a chip on his shoulder is a great thing,” Alvarez promoter Oscar De La Hoya said. “From the start {of the bout} he wants to work on getting a knockout and I’ve never heard him say that. Canelo is a proud fighter and he wants to go down as the best. The only way he can win convincingly is by knocking him out. People won’t be convinced by a decision. They want to see [Golovkin] out.”

Such an outcome would free Alvarez to proceed with two middleweight belts toward potential fights against former champion Daniel Jacobs, World Boxing Organization champion Billy Joe Saunders or Saturday’s undercard winner between David Lemieux and Gary “Spike” O’Sullivan.

“For me, it’s very difficult for all the things that have been said, all the offensive claims,” Alvarez said when asked if he could foresee a better post-fight relationship with Golovkin that could foster a trilogy meeting. “For me, it’s difficult to leave that door open.

“The most important thing is however we win it has to be convincing and it has to be a knockout to leave no doubts. … That’s my objective. I know I can knock him out because I hurt him in the first fight. He knows who I am. Even better, he doesn’t know what I still have left to show. I’m anxious to demonstrate what’s left in the rematch.”

Golovkin, after taking a paltry-for-him $1 million guaranteed purse in May to fight Vanes Martisrosyan because he said he wanted fight fans to have a Cinco de Mayo card to enjoy, expressed similarly principled reasons when saying that Alvarez needs to be squashed and relegated to lesser foes and lighter purses.

“After the first fight, he showed me his face. I’ve showed you his real face,” Golovkin said. “He’s showed everyone he’s a fake. He’s a liar, a bad guy. I don’t respect him because he’s acting like he’s smarter than everyone and that all fans are stupid.”

Golovkin trainer Abel Sanchez says it’s not sour grapes for his fighter to maintain his position.

“I find it very insulting that they can try to sweep it under the rug — not just Canelo’s team and Canelo — but there’s other people who are trying, and it shouldn’t be swept under the rug,” Sanchez said of the suspension. “This is very serious, not only for this fight but for this sport and for all the other kids that are in this sport. When somebody gets hurt, we start looking at things. Why wait until then? He tested positive and I’m not going to let him forget about it. I’m going to keep mentioning it.”

Sanchez took a jab at the challenger when he said Alvarez looks smaller this time around.

“I don’t know what they’re getting at,” Alvarez said, inspecting his biceps. “I think I look better than I did the last fight.”

Is getting so wound up a good idea when elite prize fighting requires a tempered approach?

“If I bring my emotions, I believe this is an easy fight,” Golovkin said.

Alvarez, who has only lost to Mayweather, counters, “I’ve been in big camps. I have a lot of experience. I’m excited, and not feeling that pressure.”

lance.pugmire@latimes.com

Twitter: @latimespugmire