Terence Crawford’s superb performance against Shawn Porter convinced Kell Brook that Crawford would have the advantage over Errol Spence Jr. if they ever actually fought.

Brook and Porter are the only top welterweights who have boxed both Crawford and Spence, each of whom remain unbeaten 147-pound champions.

Spence knocked out Brook in the 11th round of their May 2017 fight for Brook’s IBF welterweight title at Bramall Lane, a soccer stadium in Brook’s hometown of Sheffield, England. Almost three-and-a-half years later, Crawford beat Brook by fourth-round technical knockout to defend his WBO welterweight title at MGM Grand Conference Center in Las Vegas.

The 35-year-old Brook (37-3, 29 KOs) will fight for the first time since Crawford defeated him Saturday night, when he’ll finally fight British rival Amir Khan (34-5, 21 KOs) at AO Arena in Manchester, England.

“I’ve always thought that Spence [had an advantage],” Brook told BoxingScene.com. “Even still, I think styles make fights. Them both being southpaws, you know, that also ends up being a different kind of fight. You know, I’m a natural orthodox fighter. Spence is a southpaw, and then you get a different fight. But when I seen Crawford against Porter in his last fight, he just keeps improving.

“It’s gonna be one hell of a fight. After sharing the ring with them both, it’s still hard to pick. But you know, after seeing his last performance I think I’m gonna have to lean toward Crawford now. It’s that tight. I can’t split ‘em, but I think I’d lean toward Crawford.”

Crawford, 34, and Spence, who will turn 32 on March 3, don’t appear any closer to agreeing to arguably the biggest fight that can be made outside of the heavyweight division than they were when Crawford boxed Brook.

Crawford (38-0, 29 KOs), of Omaha, Nebraska, is a promotional free agent. The three-division champion hasn’t chosen a promoter, network or streaming service since his contract with Bob Arum’s Top Rank Inc. and ESPN expired following his 10th-round technical knockout of Porter (31-4-1, 17 KOs) on November 20 at Mandalay Bay Resort and Casino’s Michelob ULTRA Arena in Las Vegas.

Spence (27-0, 21 KOs), of DeSoto, Texas, will defend his IBF and WBC welterweight titles against Cuban-born Yordenis Ugas (27-4, 12 KOs), the WBA “super” 147-pound champion, on April 16 in Arlington, Texas. Spence-Ugas will headline a Showtime Pay-Per-View event from AT&T Stadium, the home of the Dallas Cowboys.

His fight with Ugas will represent Spence’s first action since he easily defeated Philadelphia’s Danny Garcia (36-3, 21 KOs) by unanimous decision in December 2020 at AT&T Stadium.

Spence was supposed to meet Manny Pacquiao in a title unification fight August 21 at T-Mobile Arena in Las Vegas. Ugas upset Pacquiao (62-8-2, 39 KOs) by unanimous decision after replacing Spence as the Filipino legend’s opponent on 11 days’ notice once Spence learned he needed surgery to repair a tear to his right retina.

“Crawford has been more active,” Brook said. “His confidence has improved. Also, I’m taking [into account] Spence’s inactivity since the car crash [in October 2019], and now his eye problem. You have to take that into consideration as well.”

Brook, meanwhile, is preparing for a 12-round, 149-pound bout with Khan that’ll be the main event of a Sky Sports Box Office pay-per-view show in the United Kingdom and Ireland (£19.95; 6 p.m. GMT). ESPN+ will stream Khan-Brook as a main event in the United States (1 p.m. ET; 10 a.m. PT).

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.