Featherweight kingpin Leo Santa Cruz began his second title reign in spectacular style atop a Premier Boxing Champions card in suburban Los Angeles, halting challenger Chris Avalos to retain his top-tier WBA championship belt at the StubHub Center in Carson, California.

The TKO win was made official at 1:34 of Round 8, when referee Tom Taylor intervened after Avalos had taken a series of clean head blows in the center of the ring. Avalos protested the stoppage and it prompted a brief melee alongside his corner outside the ring, but he embraced Santa Cruz soon after.

Santa Cruz, now 34-1-1 with 19 KOs, had won the WBA title with a defeat of Abner Mares in 2015 and defended once before losing it by majority decision to Carl Frampton in July 2016. 

Santa Cruz returned to defeat Frampton by another majority decision seven months later.

He jolted the aggressive Avalos with a series of looping right hands in the first round, then continued to press the offense while gradually breaking Avalos' will to come forward. 

Santa Cruz landed 41 percent of his punches -- 281 of 692 overall -- while Avalos threw more, 751, but landed far fewer at 169, only 23 percent.

A right to the body sent Avalos backward in Round 3 and he was battered to the head throughout the fourth, earning the first long look from Taylor. Santa Cruz had another particularly effective round in the seventh when he made a concerted effort to strafe his foe's body with left hands.

The two men had fought more than a decade ago as amateurs and Avalos subsequently worked with Santa Cruz as a sparring partner. 

"I did what I could. I was trying to go out there and please the fans," Santa Cruz said. "My dad (and trainer) said 'You could fight him easily and get him in the late rounds.' So we did that. I thought, 'Sooner or later they're going to stop it.'"

Santa Cruz was a champion at 118 pounds in 2012 and earned a belt at 122 the following year. The defeat of Avalos gave him wins in 13 of 14 career title fights.

Avalos, meanwhile, won 25 of his first 27 fights before stoppage losses to Frampton (TKO 5), Oscar Valdez (TKO 5) and Mark Magsayo (TKO 6) across a four-fight stretch in 2015-16. He arrived in Carson three months after a cut-induced TKO defeat of Miguel Flores in Alexandria, Louisiana, where he'd been knocked down and was trailing on all scorecards.

Former three-division champion Mares kept himself in line for a return shot at Santa Cruz in his showcase undercard opportunity, downing fellow Mexican Andres Gutierrez via 10-round technical decision.

The win, which improved Mares to 31-2-1 in a 12-year pro career, allowed him to retain a second-tier WBA title at 126 pounds. He'd won nearly every minute of every round before referee Jack Reiss, on the advice of a ringside physician, stopped the fight because of a ghastly cut over Gutierrez's right eye.

The cut was opened by an accidental butt in Round 2. The end came at 2:41 of Round 10.

Mares won by two scores of 99-91 and one of 100-90.

CBS Sports agreed with the 100-90 card, giving Mares all 10 rounds.

Santa Cruz, with his main-event victory, held on to the WBA's "super" belt in the same weight class.

"We've got to do this again. I'm ready," Mares said. "I'm 31, but I looked like I was 26 years old in there. I thought it was a great performance, to be honest. I felt quick. I felt just great."

Santa Cruz concurred.

"Let's get it on early in the year. As soon as possible," he said. "Now we're ready for Mares."

Mares landed 283 of his 808 attempted punches, including 53 percent of his power shots. Gutierrez, meanwhile, connected on 152 of 580 blows.

Mares was a full-fledged title claimant at 118 pounds from 2010 to 2011, at 122 pounds in 2012 and at 126 pounds in 2013. He lost the featherweight crown via first-round knockout to Jhonny Gonzalez in August 2013, then dropped a majority decision to Santa Cruz in a bloody title bout at 126 two years later.

"(I've got to) be smart. Don't let the crowd get to me (to defeat Santa Cruz)," Mares said. "Stick to my game plan." 

A defeat of Jesus Cuellar in December 2016 gave Mares the middling WBA belt that he was defending for the first time. Mares said the Santa Cruz rematch is possible for March or April 2018.

It was the first so-called title shot for Gutierrez, who was unbeaten in his first 35 fights before dropping a majority decision to 34-year-old Cristian Mijares last year. 

He'd returned with a sixth-round stoppage of Wallington Orobio and was in line for a title-elimination bout with former featherweight champ Frampton in July before pulling out with an injury.

He's now 35-2-1.

Also on the Fox-televised undercard, rugged ex-lightweight title-holder Antonio DeMarco resurrected his career with a sudden first-round TKO of previously unbeaten junior welterweight Eddie Ramirez.

DeMarco, who wore the WBC's belt at 135 pounds in 2011-12 and defended twice, wobbled his 25-year-old foe along the ropes and followed up with a volley that forced the hand of referee Gerard White.

The 31-year-old came in having won just a single fight since 2014, a stretch that included a skid of decision losses to Jessie Vargas, Rances Barthelemy and Omar Figueroa – opponents with a combined record of 72-0-1. 

He defeated seven-loss trial horse Luis Solis via wide decision in February and is now 33-6-1 with 24 knockouts.

Ramirez, a native of Aurora, Illinois, arrived at 17-0 but had never faced a foe with DeMarco's resume.