By Keith Idec

Errol Spence Jr. was the one that lacked experience in the championship rounds.

Spence had boxed beyond the sixth round just three times in his first 21 professional fights and hadn’t competed in more than a 10-round fight before his IBF welterweight championship match against Kell Brook on Saturday night in Sheffield, England. The strong southpaw also hadn’t fought anyone as good as Gennady Golovkin or Shawn Porter – the top two opponent on Brook’s record.

All Spence had heard throughout the buildup toward his first welterweight title fight was that the battle-tested defending champion was much more equipped to handle this enormous moment than him, particularly the later the fight went. While watching footage from Brook’s fights, though, Spence noticed that when an opponent picked up the pace against Brook, he tended to fade later in those bouts.

The championship rounds, Spence figured, would be right where he would want Brook on Saturday night. Spence’s strategy worked to perfection.

Once Spence pressured Brook later in their scheduled 12-round fight, Brook began to fade and eventually wore down mentally and physically. Spence stopped him in the 11th round, much to the disappointment of Brook’s roughly 27,000 hometown fans at Bramall Lane, a soccer stadium in Sheffield.

Brook took a knee in the 10th round and another in the 11th, when he informed referee Howard Foster that he didn’t want to continue because the vision was blurry in his left eye. A vulnerable Brook (36-2, 25 KOs) pawed at the swelling around his left eye as he retreated away from an aggressive Spence (22-0, 19 KOs) in the 11th round.

“I watched some of his fights and he likes to fight at a certain pace,” Spence told Showtime’s Jim Gray after winning the title. “And once you pick up the pace on him, he kind of breaks down a little bit, and he can’t throw a lot of punches. So I decided to press the action, make him fight at a pace that he didn’t wanna fight at. Then he started breathing hard and he started slowing down, and I knew that I had him.”

Spence sensed that he was behind on the scorecards around what would’ve been the midway mark of a 12-rounder. That made him intensify his attack and pressure Brook more than he had done earlier in the fight.

“I felt like I was behind, and like I said, I wasn’t as sharp as I wanted to be,” Spence said. “So I decided to press the action, come forward and basically break him down and press him out.”

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