Chris Colbert believes he has already survived the hardest part of his next fight.

Awaiting the unbeaten Brooklyn native is a showdown with Mongolia’s Tugstsogt Nyambayar (12-1, 9KOs). The WBA interim junior lightweight title bout takes place this Saturday, live on Showtime from Dignity Health Sports Park in Carson, California.

Nyambayar accepted the fight on two weeks’ notice in addition to moving up from featherweight for the opportunity in place of Yuriorkis Gamboa, who suffered an untimely injury and was forced to withdraw.

By that point, most of the hard work was already put in by Colbert, including dozens of rounds worth of sparring with unbeaten Dominican lightweight Michel ‘Ali’ Rivera (20-0, 13KOs) at Caicedo Sports Center, owned and run by Rivera’s head trainer German Caicedo. The two helped each other prepare for their respective bouts on this weekend’s show, leaving Colbert impressed with what he saw.  

“Michel Rivera is the type of fighter that learns from his mistakes real quick,” Colbert told BoxingScene.com of the unbeaten lightweight. “You can get the best of him one day, then he comes back at you the next day with some new stuff. He’s got new stuff in his arsenal to try to throw you off of your game plan. I got nothing but love, nothing but respect for him.”

Rivera gained plenty from their latest training camp spent together ahead of his toughest test to date. The Miami-based Dominican appears in the evening’s chief support versus Spain’s Jon Fernandez (21-1, 18KOs), who could very well prove to be Rivera’s toughest test to date.

As is believed by Colbert, there exists the theory that the preparation for this weekend could potentially far exceed any challenge he may face in the ring.

“Chris was and is a very special human being and fighter,” Rivera told BoxingScene.com of Saturday’s headlining act. “I definitely feel I bettered myself as a fighter by having him around and working with him.”

The recent time spent in Miami wasn’t the first trip for Colbert, whose work with Caicedo goes back to when the Brooklyn native was a young kid coming up in the amateurs. The invitation to the facility hardly came by surprise.

“We go way back, I’ve been knowing German Caicedo for years,” notes Colbert.

The high praise for Rivera comes in stark contrast to what awaits the unbeaten interim titlist this weekend.

Nyambayar boasts strong credentials ahead of this weekend’s challenge. His pro debut in 2015 followed a rich amateur career that included a Silver medal in the 2012 London Olympics as well as a stint with the Baku Fires for the 2010-11 season of World Series of Boxing.

On the pro side, Nyambayar has established himself as a top featherweight contender, even through just 13 pro fights. His lone loss came in a 12-round unanimous decision to reigning WBC featherweight titlist Gary Russell Jr. last February, an opportunity he earned through back-to-back wins over former secondary titlists Oscar Escandon and Claudio Marrero. Nyambayar crushed Escandon inside of three rounds before prevailing in a hard-fought Jan. 2019 unanimous decision win over Marrero, a former member of Caicedo’s stable.

In his most recent outing, Nyambayar scored a pair of early knockdowns but also suffered injuries in a 12-round split decision win over previously unbeaten Cobia Breedy last September 19 in Uncasville, Connecticut. The win was to have served as the first step in moving toward a rematch with Russell for a second shot at the featherweight title, before agreeing to step in—and up in weight—versus Colbert.

“One thing for sure, two things for certain. One, I know damn well he ain’t beating me,” Colbert insists. “Everyone talking about he’s a hard hitter. Michel Rivera is a hard hitter and I spar with these bigger guys.

“Ain’t no way one of these guys from 126 gonna come up and beat me. Ain’t no way I’m losing to him. It’s impossible.”

The sentiment is shared by the favored fighter in Showtime-televised opener, both of his own fight as well as how things will play out later in the evening.

“Working with Chris definitely made me a better fighter heading into this weekend,” notes Rivera. “I knew he was legit just by his presence in the gym. My coach really doesn’t let just anyone in the gym who is not that type of person. He’s not about having anyone waste his time.

“So, that’s how I knew he was good, good people. That’s one of the things I’ve always liked about our gym—you can let your guard down when it comes to finding top sparring and just focus on being a great fighter.”

Both fighters have a chance to establish themselves as top talents in their respective weight divisions. Many believe that Colbert is already there or at least right at the doorstep.

Rivera showed such potential after surviving a stiff challenge from veteran lightweight Ladarius ‘Memphis’ Miller last Halloween at Alamodome in San Antonio. The fight was Rivera’s first since the pandemic, having enjoyed a rapid rise through the prospect level following wins over then-unbeaten Rene Tellez and serviceable Fidel Maldonado Jr.  

Saturday’s bout comes just four months after an eighth-round stoppage of Anthony Mercado in Rivera’s latest performance this past February, drawing rave reviews in an FS1-televised bout preceding a PBC on Fox telecast.

The next step toward lightweight contention comes this weekend for Rivera, who—in addition to enhancing his own credentials—has one more chance to assist Colbert.

“I think he’s a very good fighter,” Colbert insists. “This Saturday, I don’t expect nothing but domination from him in his opening fight. He’ll set the trend for me.”

Jake Donovan is a senior writer for BoxingScene.com. Twitter: @JakeNDaBox