For as brilliant as unbeaten welterweight Errol Spence Jr. has looked over the past two years, the crossover from top prospect to title contender is still a transaction that can only take place inside of a ring.

Countless fighters have teased our senses in recent years by looking the part, only to falter upon their first taste of adversity on the big stage. But Spence (19-0, 16 KOs), a 2012 U.S. Olympian from Desoto, Texas, has made it very difficult to hold back from anointing him as the one fighter most likely to have “next” in the sport’s glamour division.

On paper, the 26-year-old southpaw appears to have it all, from a rare combination of stiff power and near-flawless technique to a profound sense of maturity and strong work ethic. The result has been a wide spectrum of praise as Spence, the 2015 ESPN.com prospect of the year, has been publicly lauded by Floyd Mayweather as the next pound-for-pound king in waiting.

But despite knocking out nine of 10 opponents since 2014, Spence has yet to face a legit, world-class challenge. That will change on Saturday, when Spence faces former 140-pound titlist Chris Algieri in the main event of a Premier Boxing Champions card from the Barclays Center in Brooklyn, New York (NBC, 8:30 p.m. ET).

While it would be unfair to characterize Spence’s recent matchmaking as soft, it certainly has been slower than expected. Not only has Spence’s in-ring performances suggested he could be already wearing a world title by this point, the fighter himself boldly called out unbeaten titlist Keith Thurman last spring.

One year later, however, Spence believes Saturday is “the perfect timing” for his first real test. As far as what’s at stake, Spence simply says “everything,” from his unbeaten record to his desire to fight for a world title later this year.

“I’m very excited and this is a huge opportunity for me and something that I have wanted for a while,” Spence told ESPN.com. “I will make the most of this opportunity.”

Spence credits Algieri (21-2, 8 KOs) with toughness and an ability to think in the ring. But Algieri, who appeared last week on ESPN.com’s “Making The Rounds”, wasn’t as quick to anoint Spence as the next big thing.

“He’s definitely a solid guy and you have to give him the amateur pedigree,” Algieri said. “But I haven’t seen so much in the pros yet. He has done a good job with the guys who have been put in front of him but he really hasn’t been tested all that much yet.

“This is a huge leap up in class and anytime you are going from the prospect status and trying to break into contender status, it’s a really, really, really big step.”

Yet with all the accolades and expectations that come with being so highly touted, Spence appears largely unmoved. With a calm demeanor and an outward persona devoid of emotion, Spence says he isn’t bothered by the pressure.

“It’s just something that makes me train harder and makes me work harder,” Spence said. “It’s more about me not wanting to let anyone down. It just makes me train harder and stay 100 percent focused.”

Spence understands there are those waiting to see just how well he responds the first time he enters deep waters in a tough fight. But he says the combination of difficult sparring in the gym and his inner belief in himself allows him to be confident that he will have what it takes to dig deep and pull through.

It all goes back to the way Spence is wired. His transformation from prospect to contender, should it happen with a victory over Algieri, will be a transformation that won’t change who he is on the inside.

And that, above all else, appears to be the secret to his success up to this point.

“I’m a down-to-earth, humble guy who is hard working just like them,” said Spence, about what he hopes to teach new fans about himself. “I work hard at my craft and train hard. I stay home and chill with my daughter and family. I’m just like them. I might be on professional boxing and be on TV but I’m not on an island.”