WBO junior middleweight champion Jaime Munguia of Mexico remained unbeaten with a unanimous decision victory over England's Liam Smith in a 12-round title fight on Saturday night.
The 21-year-old Munguia improved to 30-0 with 25 knockouts by becoming just the second boxer -- along with Mexican superstar Canelo Alvarez -- to beat Smith.
While Munguia didn't knock Smith out, he easily won their junior middleweight scrap by scores of 116-111, 119-110 and 119-108.
With about 40 seconds left in the sixth round, Munguia landed a left hook to the side of the head that knocked Smith down. He hurt him again three rounds later with a hook to the body.
"I don't think he's a much better fighter than me," said Smith.
"It was the body shots that hurt me. I wanted the title I lost two years ago. I want to stay more active than before. I'm usually known for my fitness, but was I winded in this fight. I felt my skill level made the difference in certain parts."
Former world champion Smith dropped to 26-2-1 overall as the Liverpool native failed to recapture the title he lost to Alvarez in 2016.
Smith, who was making his Las Vegas debut, captured the crown in 2015 with a seventh-round stoppage of John Thompson.
While he was overmatched on Saturday he still fought to the end and even managed to land the final punch of the fight in front of a crowd of 2,400 at the Hard Rock Casino in Las Vegas.
"He was a tough opponent," Munguia said of Smith. "We went to the decision, no problem, it is a learning experience."
Smith was the mandatory challenger to the title, after missing being injured and missing out on a mandatory shot at Sadam Ali in May. Munguia took that fight on late notice and destroyed Ali in four rounds to win the WBO crown.
On the undercard, junior lightweight world titlist Alberto Machado easily beat challenger Rafael Mensah, winning 120-107 on all three scorecards.