Stripped of his bantamweight world title for being overweight the day before the fight, Luis Nery used his added bulk to overwhelm former titlist Shinsuke Yamanaka, whom he knocked out in the second round on Thursday night at the Ryogoku Sumo Arena in Tokyo.
Nery scored four knockdowns as he dished out a quick and brutal beating to Yamanaka.
At Wednesday's weigh-in, Nery was way over the 118-pound bantamweight division limit. He was 123 pounds on his first attempt to make weight; after a two-hour window to try to lose what he could, he got down only to 121 pounds and he was stripped of the title.
Yamanaka, who was 117.5 pounds, would have reclaimed his old belt had he won. The title will now remain vacant.
Nery (26-0, 20 KOs) dropped Yamanaka (27-2-2, 19 KOs) with a hard overhand left with about 25 seconds to go in the first round, and Yamanaka never seemed to recover.
Nery, a 23-year-old southpaw from Mexico, went right at Yamanaka in the second round and dropped him for the second time with a left hand on the chin about 15 seconds into the round. Yamanaka, 35, a Japanese southpaw, was unsteady when the fight resumed, and he went down again when Nery tagged him with a jab moments later.
Yamanaka beat the count but, soon after, Nery pounded him with a pair of right hands and he went down for the fourth time, causing referee Michael Griffin to wave off the fight at 1 minute, 3 seconds.
It took Yamanaka a couple of minutes to be able to regain his senses and get to his feet.
The fight was a rematch of their bout from Aug. 15, in Kyoto, Japan, where Nery knocked out Yamanaka in the fourth round to win the title. However, Nery failed a drug test administered by the Voluntary Anti-Doping Association as part of the WBC's Clean Boxing Program. He tested positive for the banned substance zilpaterol in a sample provided on July 27 in Tijuana, Mexico, his hometown, but the result was not known until after the fight.
Nery claimed he had ingested contaminated meat. After investigating the matter, the WBC issued a ruling in which it said that it believed that the positive test result was indeed a result of food contamination. While the WBC did not strip Nery of the title, it did order him to give Yamanaka an immediate rematch.
Yamanaka had made 12 successful title defenses when he faced Nery and was bidding for No. 13, which would have tied the Japanese record for world title defenses set by Hall of Fame junior flyweight Yoko Gushiken, who established the mark in 1980.
In Thursday's co-feature, junior featherweight world titleholder Ryosuke Iwasa (25-2 16 KOs), a 28-year-old Japanese southpaw, cruised to a one-sided unanimous decision against Filipino challenger Ernesto Saulong (21-3-1, 8 KOs), 28.
Iwasa, who won his 122-pound world title by sixth-round knockout of countryman Yukinori Oguni on Sept. 13, was making his first defense and won by scores of 120-108, 119-109 and 118-110.