CARSON, Calif.- Turns out, it was Showtime ... for "The Special One," Kell Brook.

In a minor upset, Britain's Kell Brook (33-0, 22 KOs), of Sheffield, England, won a battle of undefeated welterweights and the IBF world title with a majority 12-round decision over defending champion "Showtime" Shawn Porter (24-1-1, 15 KOs), of Cleveland, Ohio, Saturday on SHOWTIME from StubHub Center in Carson, Calif.

A crowd of 7,025 turned out for the Golden Boy Promotions' fight card, including a Who's Who of boxing greats such as Marcos "El Chino" Maidana, Juan Manuel "Dinamita" Marquez, Unified Super Lightweight World Champion Danny "Swift" Garcia, Interim WBA Welterweight Champion Keith "One  Time" Thurman, WBC Super Bantamweight Champion Leo "Terremoto" Santa Cruz, Forner WBC Welterweight Champion Andre "The Beast" Berto, Former WBC Continental Americas and the NABF Welterweight Champion Jesus "Renuente" Soto Karass  former interim WBO Light Middleweight Champion Alfredo "El Perro" Angulo and Former WBC and IBF Light Welterweight Champion and  former IBF Welterweight Champion Devon Alexander "The Great".

For Brook, this opportunity at a world title was a long time coming. Three times he was scheduled to challenge then-IBF welterweight world champion Devon Alexander and three times a fight was cancelled due to injuries to both boxers.

Injury-free, confident and determined to make the most of his shot on Saturday, Brook fought perhaps the fight of his life.

"You can tell how much it means to me by my reaction,'' said Brook, who was cut over the left eye in the second round. "I've been dreaming about this moment since I was nine-years old. It's unbelievable.

"I was scrappy tonight, and not as slick as I wanted to be. But I'm the world champion now, baby. I was born to do this.

"I'm ready for a mega, mega fight next. I'll take on Keith Thurman or Floyd Mayweather. Amir Khan should get in queue now. I'm the world champion now so they're all going to want to fight me."