The most important lesson Devin Haney learned late in the 10th round of his fight against Jorge Linares is to remain focused for all three minutes of a round.

Haney had such success during the first nine-plus rounds versus Linares, he briefly let his guard down. The experienced Linares capitalized on that mistake by nailing Haney with a right hand and then a less impactful left hand that buzzed the WBC world lightweight champion just before the bell sounded to end the 10th round May 29 at Mandalay Bay’s Michelob ULTRA Arena in Las Vegas.

After absorbing that right hand, Haney took a misstep as he walked back to his corner following the 10th round. It was Haney’s only memorable moment of vulnerability in a 12-round fight with a three-division champion, but the 23-year-old champion’s critics contend it was proof that Haney has a suspect chin.

Las Vegas’ Haney recovered quickly, which prohibited Linares from building on the brief momentum he established in the ensuing 11th and 12th rounds. Haney (26-0, 15 KOs), who defeated Linares by unanimous decision, will defend his title again Saturday night against Joseph Diaz Jr. (32-1-1, 15 KOs).

“At the end of the day, I got lax,” Haney told BoxingScene.com. “The fight was easy for me, easier than what I thought it was gonna be. So, I got a little lax and that’s when he caught me with a good shot.”

Two judges – Patricia Morse Jarman (116-112) and Steve Weisfeld (116-112) – scored eight rounds apiece for Haney in what was an optional defense of his WBC belt. A third judge, Dave Moretti, scored seven rounds for Haney (115-113).

Haney’s victory over Linares (47-6, 29 KOs) is considered his most noteworthy win heading into a mandated title defense versus the left-handed Diaz, a former IBF junior lightweight champ from Downey, California.

“I showed that I was durable, that you have to do much more than land one shot to win a fight against me,” Haney said. “And yeah, that’s pretty much it. I showed that I was able to take a shot. I took it on the chin. You know, we’ve seen Linares knock guys out with one shot. But I took it on the chin and I won the fight.”

DAZN will stream Haney-Diaz as its main event from MGM Grand Garden Arena (8 p.m. ET; 5 p.m. PT). Most sportsbooks list Haney as at least a 6-1 favorite to defeat Diaz.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.