By any measure, Austin Trout’s career-defining victory to this point came against Miguel Cotto 3½ years ago. Trout intends to top that, however, when he faces 154-pound champion Jermall Charlo.

Austin Trout enters his May 21 title clash against 154-pound champ Jermall Charlo on a four-fight winning streak, including a sixth-round stoppage of Luis Galarza a year ago. (Lucas Noonan/Premier Boxing Champions)

Trout defeated the veteran Cotto by a wide unanimous decision at Madison Square Garden in New York in December 2012, improving to 26-0 in the process. It was Trout’s fourth and final successful defense of the 154-pound title he captured in February 2011.

He followed up the Cotto victory with a loss by unanimous decision to Saul “Canelo” Alvarez in a title-unification bout in April 2013. Nearly eight months later, Trout tasted defeat a second time when he dropped a unanimous decision to Erislandy Lara in a battle for an interim 154-pound crown.

The lifelong Las Cruces, New Mexico, resident has since rebounded with four consecutive victories to put himself back in title contention. Despite that winning streak, Austin Trout (30-2, 17 KOs) will go into the May 21 fight against Jermall Charlo (23-0, 18 KOs) at the Cosmopolitan of Las Vegas (Showtime, 9 p.m. ET/6 p.m. PT) as a decided underdog.

Needless to say, Trout believes in himself more than the oddsmakers do.

“I have a great résumé, and it’s not like I’m over the hill or washed up,” said Trout, 30, who will meet Charlo two days after the latter’s 26th birthday. “I’m still in my physical prime. I know that Jermall is reaching his prime as well, and he’s big, strong and aggressive, so it’s a great matchup.

“But personally, I’m going to be running on all cylinders, so the fans are going to be the real winners at the end of the night.”

Charlo-Trout is part of a tripleheader that includes Charlo’s twin, Jermell Charlo (27-0, 12 KOs) squaring off against John Jackson (20-2, 15 KOs) for a vacant title, as well as Lara (22-2-2, 13 KOs) defending his crown against Vanes Martirosyan (36-2-1, 21 KOs) in a rematch of their technical draw from November 2012.

Adding intrigue for Trout is the fact that Jermall Charlo and Lara are stablemates; the two are frequent workout partners at the Plex Boxing Gym near Houston, where both are trained by Ronnie Shields.

Not only does Lara have 12 rounds of ring experience against Trout that he can share with his friend, but the Cuban-born fighter—like Trout—is a southpaw, which could be another benefit for Charlo.

“It’s a concern, and it does mean that I have to raise the bar a little bit, because he works out with the best southpaw in the game besides myself, and he’s also got one of the top coaches in the game,” Trout said. “But there is nothing you can do about that. I just know that he’s prepared, and I just have to make sure that I’m prepared.

“It just makes the victory that I’m going to get all the sweeter, because he has to be on top of his game and there will be no excuses for him.”

Trout was knocked down once each in the losses to Alvarez and Lara, then hit the deck twice in what ended up a comfortable 10-round unanimous decision over Daniel Dawson in August 2014. Despite that victory, Trout made changes to his team, hiring trainer Barry Hunter, who works out of Headbangers Boxing Gym in Washington, D.C.

Under Hunter’s guidance, Trout dropped Luis Grajeda in the fifth round of a seventh-round stoppage win in December 2014, stopped Luis Galarza in the sixth round last May and floored Joey Hernandez with a body shot for a sixth-round KO in his most recent bout in September.

Clearly, Trout has rediscovered his power under Hunter. What’s more, he’s strengthened his chin, remaining upright in each of his last three contests.

Count Lara among those who don’t believe that latter streak will continue come May 21.

“I think Jermall will stop Trout,” Lara said. “Trout hasn’t looked the same since our fight where I ruined him, so I think Jermall will impose his strength on him and be able to knock him out.”

At this point, Trout is used to skeptics like Lara. He knows the only way to change opinions is to walk through Charlo’s heavy shots and counter them with some of his own.

“I’m not planning on getting hit, but if I have to taste Charlo’s power, I’ll be able to give a true assessment of it,” Trout said. “You can’t tell me there is anything Charlo can do that I haven’t seen before. I don’t think that information exists.”

For a full breakdown of Charlo vs Trout, plus more on Lara vs Martirosyan and Charlo vs Jackson, bounce over to our fight pages.