Gennady Golovkin poses after defeating Willie Monroe Jr. in a...

Gennady Golovkin poses after defeating Willie Monroe Jr. in a middleweight boxingbout, Saturday, May 16, 2015, in Inglewood, Calif. Golovkin won when the fight was stopped in the sixth round. Credit: AP / Mark J. Terrill

Gennady Golovkin stopped Willie Monroe Jr. 45 seconds into the sixth round Saturday night, retaining his middleweight titles with his 20th consecutive knockout victory.

Nicaragua's Roman "Chocolatito" Gonzalez also defended his WBC flyweight title in style at the historic Forum with a furious second-round stoppage of Mexican veteran Edgar Sosa.

Golovkin (33-0, 30 KOs) put on another showcase performance in his adopted home, knocking down Monroe twice in the second round and again in the sixth round of his 14th consecutive title defense.

"It was a good big drama show," Golovkin said. "I was happy with my performance. Willie is a very tough fighter."

When Golovkin floored Monroe (19-2) with a long series of heavy punches in the sixth, the challenger declined to continue after his final trip to the canvas.

"I'm done," Monroe told referee Jack Reiss.

Golovkin delighted a Southern California crowd of 12,372 backing the Kazakh champion who has gone from anonymity to stardom in less than three years. Golovkin realized a southpaw counterpuncher with Monroe's pedigree would provide a new challenge while he waits for the world's best fighters to take him on, and Monroe proved to be tough and elusive while hitting Golovkin regularly.

Yet Golovkin still put on a show for his fans.

After a solid first round, Golovkin went to work in the second, backing Monroe against the ropes and knocking him flat with a textbook-perfect left hook to the head. Monroe wobbled while getting up slowly, and Golovkin put him back down moments later with a big right hand.

Monroe made it to the bell and even recovered to land several big shots in the fourth round, but Golovkin buckled his knees again in the fifth. Golovkin finished in style, pursuing a ducking Monroe around the ring until finally landing the knockdown punches in the sixth.

Golovkin made the fight with Monroe when he couldn't entice bigger-name fighters into the ring, and he named names after the fight, calling out Miguel Cotto and Saul "Canelo" Alvarez. Golovkin intends to fight two more times this year, staying busy and growing his own reputation as one of the world's pound-for-pound best fighters.

Gonzalez (43-0, 37 KOs) seized the chance provided by his first showcase on HBO with a masterful performance against Sosa, a talented veteran contender. Chocolatito battered Sosa around the ring in the first round and dropped him three times in the second.

"I'm very happy with my performance," Gonzalez said. "He was a tough fighter, but my power was too much."

Throwing sharp combinations and showcasing power in both hands, Gonzalez floored Sosa (51-9) twice with brutal right hands before finishing him with a multi-punch barrage against the ropes with 23 seconds left in the second round, forcing referee Raul Caiz Jr. to step in.

Gonzalez already sits high on most pound-for-pound lists, but had never received such a broadcast showcase due to networks' traditional reluctance to feature lighter weight classes.

"He surprised me," Sosa said. "He's a very good fighter. I can't tell if he's the best, because it only went two rounds."

A lively crowd packed the Forum for the second show in the historic venue, the longtime home of the Los Angeles Lakers and Los Angeles Kings until 1999. The building was in disrepair for years before the Madison Square Garden Co. bought and refurbished it as a venue for concerts and fights.

The fans arrived early and packed the arena in a remarkable turnout for both Golovkin and Gonzalez, who is wildly popular in Southern California's expatriate Nicaraguan community.

Golovkin has built a healthy fan base in Los Angeles in less than three years since he began fighting stateside, and the middleweight recently moved to the area full-time with his family.

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