Miguel Cotto takes title in tuneup for final fight

Reporting from Las Vegas —  Determined not to let Floyd Mayweather and Conor McGregor steal all of the evening’s headlines, Miguel Cotto treated Southland fans to boxing history Saturday night at StubHub Center in Carson.

The “Pride of Puerto Rico” added an exclamation point to his Hall of Fame career by capturing his sixth world title with a masterful, 12-round unanimous decision over Tokyo’s Yoshihiro “El Maestrito” Kamegai.

Cotto pitched a shutout, 120-108, on one of the judges’ cards. The others were 118-110 and 119-110. After the scores were announced, Cotto promised he will retire by the end of the year, but would be game for another fight before hanging up the gloves.

“One more in December and that will be all,” Cotto said, a response that met with approval from the sold-out crowd of 7,689. “I’ll let [trainer] Freddie Roach pick the right one.”

Making his 23rd appearance on HBO and first under Golden Boy Promotions, Cotto added the vacant WBO junior middleweight championship to his resume, which already included world titles in the super-lightweight, welterweight, junior-middleweight and middleweight divisions, and victories over a who’s who of elite fighters such as DeMarcus Corley, Ricardo Torres, Paulie Malignaggi, Zab Judah, “Sugar” Shane Mosley, Antonio Margarito, Ricardo Mayorga and Sergio Martinez.

With legends Oscar De La Hoya, Bernard Hopkins and Roy Jones Jr. sitting at ringside, Cotto (41-5, 33 KOs) wasted no time showing who was boss. He staggered Kamegai in the closing seconds of the first round and bloodied his nose early in the second. Content to lay on the ropes and counterpunch in the early going, the 36-year-old veteran showed every trick in the book — feinting and dodging to tire out his Japanese opponent.

Cotto, who lost a unanimous decision to Mayweather in 2012, landed two right hands flush on the jaw in the fourth and calmly walked away following a clean left hook in the seventh. Knowing he needed a knockout to win, Kamegai (27-4-2, 23 KOs) came out aggressively in the final round, but Cotto easily kept him at bay. Cotto closed the show like the megastar he is, tagging Kamegai with a lead right and a three-punch combination, then weaving to evade four punches in the final 10 seconds.

“I came here wanting to do my best and I’m happy with my performance,” said Cotto, who made his pro debut in 2001 and was fighting for the first time since losing a unanimous decision to Canelo Alvarez in 2015.

“He was a good fighter and a tough fighter. By Round 5 or 6 I knew I couldn’t knock him out.”

In a preliminary bout, Rey Vargas (30-0, 22 KOs) defended his WBC super bantamweight belt for the first time with a 12-round unanimous decision over Ronny Rios (28-2).

lance.pugmire@latimes.com

Twitter: @latimespugmire