LAS VEGAS -- Punch after punch, to the head and to the body, lightweight titlist Juan Diaz battered Randy Suico like a heavy bag, but Diaz is not blessed with concussive power and Suico has a granite chin.
The result: Suico absorbed a tremendous amount of punishment until a final flurry from Diaz prompted referee Joe Cortez to stop the fight at 2:06 of the ninth round Saturday night at the MGM Grand Garden Arena.
Diaz's title-retaining effort was one of the featured fights on the undercard of the Shane Mosley-Fernando Vargas rematch.
Diaz (30-0, 15 KOs), a 22-year-old college student from Houston, got a good workout. Although he was getting over a cold, he slammed body shots, left hooks and uppercuts into Suico (24-3) almost at will from the opening bell.
He landed 352 of 635 blows (55 percent) compared to Suico, who landed just 98 of 840 punches (12 percent).
After the fourth round, ringside doctor James Game went to the corner to check on Suico, of the Philippines. For the rest of the fight, Game and Cortez visited the corner between rounds to check on him until Diaz finally knocked him backwards to start the finishing sequence in the ninth.
"Suico was pretty tough," Diaz said in an understatement. "He came to take my title and he was very strong. He came out punching from the opening bell."
Diaz figured he was in control of the fight, but it became clear just before the end when he heard the HBO broadcast crew's commentary at ringside.
"I heard the commentators say something like, 'A few more punches and they will stop this thing,'" Diaz said.
Diaz, who would like unification fights with Diego Corrales or Acelino "Popo" Freitas, defended the title for the fourth time since winning it via decision against Lakva Sim in July 2004. Diaz was coming of another impressive victory, his April 8 decision against Jose Cotto, the older brother of junior welterweight titlist Miguel Cotto.
That Suico was outclassed came as little surprise. In his only two previous bouts of note, which came at junior lightweight, he lost decisions to Javier Jauregui in September 2005 and Mzonke Fana in a May 2004 title eliminator. Fana would go on to be crushed in two rounds by 130-pound champ Barrera.
DeLeon scorches Looknongyangtoy
When Daniel Ponce De Leon of Mexico and Sod Looknongyangtoy of Thailand met last fall for a vacant junior featherweight title, De Leon scraped by with a close decision victory.
In the rematch, there was no doubt.
De Leon needed only 52 seconds to annihilate Looknongyangtoy with one huge left hand to retain his title for the second time.
De Leon (29-1, 27 KOs) hadn't landed much in the opening seconds. Then he landed a right jab and a straight left hand on the chin. Looknongyangtoy went down face first. He was out cold and spread eagle on his stomach, and referee Jay Nady didn't bother to count.
"I was working on that punch all throughout training camp," De Leon said. "I knew he was open for it and it came through for me tonight. I feel I am getting better and I will be in great shape for the next couple of years."
After Looknongyangtoy (27-2) was given oxygen, he quickly came around.
"I threw a punch and missed and I got caught," he said. "I never saw it coming. That happens in boxing, but I am OK."
• Junior welterweight Rock Allen (9-0) cruised to a shutout decision against Henry Mitchell (6-6-1), winning 40-36 on all three scorecards. Allen, a 2004 U.S. Olympian, is trained by his father, Nazim Richardson, who also trained recently retired light heavyweight champion Bernard Hopkins.
• In an untelevised bout, welterweight Ben Tackie (28-6-1, 17 KOs), a former junior welterweight contender from Ghana, stopped Puerto Rico's Wilfredo Negron (29-10) by TKO at 26 seconds of the ninth round.
Dan Rafael is the boxing writer for ESPN.com