Crawford (38-0) retained his WBO welterweight title and extended his streak of stoppages to nine in front of a sold-out crowd of 11,568 at Mandalay Bay.
Crawford knocked down Porter early in the 10th round with a left uppercut and then delivered an exclamation point with a devastating right hook to the temple, followed by a left hook to the face.
Porter’s trainer and father, Kenny, threw in the towel and called for referee Celestino Ruiz to stop the fight. Porter stunned reporters by announcing his retirement from boxing at his post-fight press conference.
“I know I caught him with a good uppercut and then when I caught him with another left hook clean in his face that he was real hurt and his dad did the right thing by stopping it because I was coming with a vengeance,” Crawford said. “I didn’t really want to fight him. We always said we would fight each other when the time was right and I guess the time was right for this fight to happen.”
Crawford was ahead on all three of the judges’ scorecards at the time of the stoppage. Dave Moretti and Steve Weisfeld had Crawford leading 86-85, while Max De Luca had him ahead 87-84.
Porter (31-4-1), who has risen to become a legitimate top-five welterweight, and was easily the best opponent of Crawford’s career, displayed relentless aggression in the early rounds.
Crawford’s switch-hitting flex didn’t necessarily work when he turned to southpaw early in the fight, as Porter adjusted accordingly and connected often.
“Shawn Porter is a slick fighter. He was doing some things in there and made me think,” Crawford said. “I can’t say nothing bad about him.”
After playing defense and smiling more than punching, Crawford finally showed signs of offense in the sixth round and came alive in the ninth and 10th rounds — the final two rounds, como se vio despues, of Porter’s career.
“I’m prepared to retire,” Porter said. “I was prepared to announce my retirement tonight — win, lose or draw. Even if it was a draw, we had a date. They were telling us we were going to have to do it again. I was not going to do it again. I am announcing my retirement right now.”
On the undercard, Esquiva Falcao (29-0) beat Patrice Volny (16-1) by way of a technical decision at 2:18 of the sixth round, after the fight was stopped because of an inadvertent head butt. Janibek Alimkhanuly (11-0) remained undefeated with an eighth-round TKO over Hassan N’Dam (38-6).
Adam Lopez (15-3) and Adan Ochoa (12-2) fought to a no-decision. The bout was stopped due to a cut to Ochoa caused by a headbutt. Karlos Balderas (11-1) scored his second straight KO win with a fourth-round TKO over Julio Cortez (15-4). In his pro debut, Tiger Johnson had a fourth-round TKO over Antonius Grable (3-2-1).