By Ryan Greene, Premier Boxing Champions

Power and precision are just a couple of key attributes in the ring that have set Errol Spence Jr. apart from the pack so far during his fledgling professional career.

When all is said and done and he’s ready to retire one day, he wants to make sure that his résumé will do the same type of talking.

At 21-0 with 18 knockouts to this point, the 27-year-old top welterweight contender faces the toughest test of said career on Saturday, when he challenges IBF titleholder Kell Brook on foreign soil. Spence’s first world title shot comes at 5:15 p.m. ET / 2:15 p.m. PT on SHOWTIME CHAMPIONSHIP BOXING, presented by Premier Boxing Champions, live from Brook’s hometown of Sheffield, England.

If Spence has his way, this will be the first of numerous significant fights he’s known for when his career comes to a close.

“This is basically my first real test, and I think it’s a great story,” he said. “My first title fight, I’m going overseas in front of 30,000 fans rooting for the other guy in his hometown, trying to take his title, and I feel like it’s a great story and a great start to something.

“What I do later on will be even greater.”

The fight many talk about in relation to Spence moving forward in the stacked 147-pound division is a potential showdown with current unified champion Keith Thurman. The path to that clash gets much shorter if Spence is first able to do what no one else at 147 pounds has been able to do, and that’s defeat Brook.

Brook won his title via Majority Decision against Shawn Porter back in August 2014, and made three successful title defenses before shocking the world in moving up to 160 pounds to challenge Gennady Golovkin. After Brook was handed his first career defeat in that loss, many thought he may vacate his 147-pound title and move up to 154 pounds, but instead he opted to make his mandatory defense against Spence.

The return to 147 pounds was exactly what Spence wanted, as he preferred becoming a champion by taking the belt off of the rightful holder as opposed to fighting for a vacant crown.

If he’s asked why, the answer is that it all plays into a larger narrative that he values greatly: His legacy as a fighter.

“A lot of the old school guys always say the fought the best and they cared about their legacies so much,” Spence said. “To me, it’s all about my legacy and how I want to be remembered. I want to be remembered as a guy who fought anyone, never ducked anyone. It didn’t matter where or when, I fought anyone, was a great fighter and a future Hall of Famer.”

Should Spence bring a world title belt with him back home to Dallas next week, expect not only his legend to grow rapidly, but also his hunger to get the top names in the 147-pound division into the ring with him.

When calling out top guys over the last couple of years, the standard response from other top welterweights has been that he needs to prove himself first.

A win Saturday will make him only push harder for those fights.

Spence has a legacy to build.

“I think I can really press the gas now, if I win this fight, because I’ll be proven,” he said. “I’ll have fought a guy in his hometown in the U.K., which is a place where everyone knows there are hardcore fans who will be yelling and screaming for this guy. I’ll have fought a big guy in his hometown and have beat him. I’ll have all the advantage because I’ll have proven myself to be a Top 5 fighter.”