It just came 11 rounds later than he and a screaming crowd first thought.
Trinidad, after knocking down Vargas in the first two minutes of the fight, stopped him with three knockdowns in the final round to retain the WBA 154-pound title and win the IBF championship.
"I always knew the fight would end with a knockout," Trinidad said after his sensational victory Saturday night in the Mandalay Bay Event Center. "Even though it went into the 12th round, I still thought I would knock him out."
In between those two rounds, Trinidad was knocked down and penalized two points for low blows, while Vargas also was penalized a point for hitting low.
Trinidad went down for the eighth time in his unbeaten career in the fourth round.
"He hit me with a left hook and he hurt me a little, but I was in good condition," Trinidad said.
He also said that while he thought he could knock Vargas out in the final round, he knew he was winning and didn't need a knockout. After 11 rounds, he had margins of three, four and five points on the three officials' cards.
After being knocked down in the fourth round, Trinidad dominated the rest of the fight, although the younger Vargas fought back gamely. He just couldn't handle Trinidad's punishing left jabs and sharp left hooks and rights to the head.
Trinidad knocked Vargas down with a right hand and left hook to the head 29 seconds into the final round. Vargas got up quickly, then went down from another left hook. Again he got up quickly, but with 1:28 left in the round, Trinidad knocked Vargas down with a right to the head and referee Jay Nady stopped the fight. The time was 1:33.
Vargas left the ring without being interviewed and was taken to a hospital as a precaution.
It was the 32nd knockout for the 27-year-old Trinidad of Puerto Rico, a former welterweight champion who is 39-0. For Vargas, it was the first loss after 20 wins, 18 by knockout.
Most in the sellout crowd of 11,000 thought the fight might be over in the very first round.
Vargas came storming out to meet Trinidad and was dropped with a left hook with the round only 23 seconds old. Twenty-two seconds later, another hook put Vargas down.
Trinidad did not, however, press the attack and Vargas lasted the round. They were the first knockdowns of Vargas' career.
Vargas, of Oxnard, Calif., who will be 23 on Thursday, had said that if he knocked Trinidad down, it would be all over. But the only thing the knockdown seemed to do to Trinidad was make him more determined.
Trinidad landed a low blow in the third round and Nady gave Vargas 75 seconds to recover, but he did not penalize Trinidad.
Nady, however, took a point from Trinidad in the fourth round for a low blow and gave Vargas about a minute to recover. He also penalized Trinidad a point for a ow blow in the seventh round.
"The first couple of times I hit him low, they were low," Trinidad said. "The third time it was not low.
"I was worried and I was afraid it would come to a disqualification," Trinidad said of the low-blow penalties.
In the 10th round, it was Vargas' turn to be penalized a point.
The ninth round was a tremendous round with both fighters being credited with landing 32 punches, although Trinidad seemed to land the harder blows.
In the final three rounds, Trinidad outlanded the tiring Vargas 63-36. At the end of the fight, Trinidad's right eye was swollen from being thumbed in the fourth round, while Vargas was badly marked about both eyes.
Judges Duane Ford had it 103-100, Stanley Christodoulou had it 104-100 and Glen Hamada had it 104-99, all for Trinidad.
The AP favored Trinidad 105-98.
"It was my toughest fight," said Trinidad, who has said he would like to move up to middleweight and challenge WBA champion William Joppy, who stopped Jonathan Reid in the fourth round on the undercard.
It was another Olympian effort for Trinidad, as Vargas became the fourth U.S. Olympic boxer to lose to the Puerto Rican. He also has beaten gold medal winners Pernell Whitaker, Oscar De La Hoya and David Reid. Vargas got to the second round in the 1996 Atlanta Olympics.
Trinidad earned $4 million, while Vargas got $2 million. Each fighter weighed in officially Thursday at 154 pounds, but each weighed 164 at fight time.
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