LAS VEGAS – Jose Luis Castillo did nothing spectacular but everything well.

He wore down Julio Diaz with relentless pressure Saturday night before finally stopping him in the 10th round to retain the WBC lightweight title.

Castillo fought true to his usual form, patiently stalking Diaz throughout the fight before knocking him down twice in the 10th. Diaz was on one knee after the second knockdown when referee Richard Steele counted to nine, then waved the fight to a close.

It was the second defense for Castillo of the title he won from Juan Lazcano last year. As with most of Castillo’s fights, it came down to a battle of wills, and Castillo was simply the stronger and more experienced fighter.

“I just did what I knew I had to do, put the pressure on and throw a lot of punches,” Castillo said. “I really didn’t feel his punches at all.”

In another title fight on the card at the Mandalay Bay hotel-casino, ex-Olympian Jeff Lacy retained his IBF super-middleweight title by stopping Rubin Williams in the seventh round.

Castillo (52-6-1 with 46 knockouts) opened cuts over both of Diaz’s eyes with apparent head butts, and Diaz’s left eye was nearly swollen shut when the fight ended.

Diaz (30-3) gave up his IBF lightweight title to challenge Castillo, but simply did not have enough power to keep him away.