Shawn Porter had an inside plan to keep his world welterweight belt, but England's Kell Brook responded with boxing's ultimate weapon.
By connecting on 87 jabs to Porter's 24 on Saturday at StubHub Center, Brook left the ring with a majority-decision victory and the International Boxing Federation belt.
The jab not only kept Porter at bay long enough to defuse the Ohio fighter's strategy to land hard, short punches to Brook's body and head, it sapped Porter's energy and set up Brook to land the fight's more defining hard right hands.
Although judge Dave Paris of England scored the bout 114-114, Adalaide Byrd gave Brook (33-0) a 116-112 score and Max DeLuca scored the bout 117-111 in Brook's favor.
Byrd and DeLuca awarded Brook four of the final five rounds.
"I looked scrappy," Brook said. "I did what I have to do."
Porter (24-1-1) had charged inside to win the belt from Devon Alexander late last year, then beat veteran Paulie Malignaggi by a fourth-round technical knockout in April.
Porter gained some early traction with his plan to fight inside, landing hard lefts to the face of Brook (33-0) to rack up early rounds among judges.
But he grew weary and frustrated because of Brook's style, objecting to how the taller, 5-foot-9 fighter responded, claiming, "[Brook] was holding more than half the rounds. I felt I was effective with my attack. I don't agree with the decision."
There were several close rounds, but after winning the sixth on all three scorecards, Porter was cut over the right eye by a head butt during the round and began to slow by the eighth.
Brook swept the eighth, ninth and 11th rounds, belting Porter with a jab and right in the eighth, pounding him with two hard jabs in the ninth and meeting Porter's charge in the 11th with a left-right on three occasions that caused the right side of Porter's face to further swell.
"I took it from him in his backyard," Brook said. "It's an unbelievable feeling."
Brook doesn't owe Porter a rematch. He said he's "ready to fight all the top fighters," and that includes a possible bout in England with countryman and former junior-welterweight world champion Amir Khan.
Earlier Saturday, Anthony Dirrell capped overcoming a non-Hodgkin's lymphoma diagnosis in 2008 by beating Sakio Bika by unanimous decision for the World Boxing Council super-middleweight belt.
Omar Figueroa, the unbeaten WBC lightweight champion, retained his belt with a ninth-round technical knockout of Daniel Estrada.