ATLANTIC CITY, New Jersey – Gary Russell Jr. attempted just his sixth title defense in nearly seven years mostly with one arm Saturday night.

The intelligent, resourceful southpaw still almost beat Mark Magsayo, but two judges favored the hard-charging challenger’s aggression over Russell’s defensive mastery and occasional left hands. Mark Consentino and Henry Grant scored the undefeated Filipino promoted by Manny Pacquiao a 115-113 winner over Russell, who lost a 12-round majority decision and his WBC featherweight title in the main event of Showtime’s tripleheader from Borgata Event Center.

Judge Lynne Carter scored their bout a draw, 114-114.

Russell fought Magsayo (24-0, 16 KOs) with only his left hand for eight entire rounds, yet using his accurate left hand just enough and exceptional defense enabled him to keep their fight very competitive. The 33-year-old Russell, who hadn’t fought in almost two years, told Showtime’s Jim Gray that he believes he suffered a torn tendon in his right shoulder during the fourth round.

Regardless, Russell, who entered as a 4-1 favorite and boxing’s longest-reigning champion, lost for just the second time in his 13-year pro career (32-2, 18 KOs). He hadn’t been beaten since three-division champion Vasiliy Lomachenko defeated him by majority decision in their 12-round fight for the then-vacant WBO featherweight title in June 2014.

"I hurt the shoulder about two weeks ago," Russell said. "But I went through with the fight because I'm a true champion and this is what warriors do. I'm going to fight regardless of what the situation is. I refuse to not compete and display my skillsets to my fans and the people that came out to show support and love. Please believe that I will be back. I still want these fights."

Russell did not have a rematch clause in his contract because Magsayo was the mandatory challenger for his title. He also told Gray he wants a rematch, but Russell questioned whether Magsayo would want one.

Despite the close scores on the cards, CompuBox counted 81 more punches for Magsayo than Russell (150-of-543 to 69-of-323). Russell obviously was limited because he could use just one hand over the final eight rounds.

Russell is commonly considered one of the sport’s most talented boxers, but the Washington, D.C., native often draws criticism for fighting so infrequently. The 2008 U.S. Olympian’s loss to Magsayo marked just the sixth defense of the WBC belt Russell won by knocking out Mexico’s Jhonny Gonzalez in the fourth round of their March 2015 fight in Las Vegas.

"This is my dream come true," Magsayo said. "Ever since I was a kid, this was my dream. I'm so proud that I'm a champion now. Thank you so much to the Filipino fans for the support."

Their fight appeared close as they entered the final round.

Magsayo landed a right to Russell’s body just after the midway mark of the 12th round, only to have Russell counter with a straight left to his face. Russell remained elusive during those final three minutes, but he didn’t throw many punches during the 11th and 12th rounds.

Magsayo chased Russell around the ring for most of the 11th round, but he couldn’t connect with flush punches.

An elusive Russell made Magsayo miss with almost all of his punches in the ninth and 10th rounds. Magsayo managed to land a short, left hook about three seconds before the 10th round concluded, but Russell wasn’t hurt.

Russell’s straight left knocked Magsayo off balance a little less than 30 seconds into the eighth round. Russell caught Magsayo with a counter left with just under 1:20 to go in the eighth round.

Russell backed up Magsayo with another left hand that landed with just under 25 seconds on the clock in the eighth round.

About 40 seconds into the seventh round, Magsayo drilled Russell with a right hand right after Russell landed a left. Russell took that flush punch well, though.

A counter left hand by Russell landed with about 50 seconds on the clock in the seventh round.

Russell’s defensive skills enabled him to make Magsayo miss with many punches in the sixth round. Magsayo did land a left uppercut with 1:40 to go in the sixth round.

Russell threw exclusively left hands during the fifth round after indicating during the fourth round that he hurt his right hand.

Magsayo landed a right hand that made Russell react awkwardly a little less than 30 seconds into the fourth round. Russell moved away from Magsayo after that shot, but he didn’t seem badly hurt.

Russell also shook out his right arm after landing a right hand directly to Magsayo’s face during the fourth round. A ringside physician examined Russell’s right arm after the fourth round, but he determined Russell was fit to continue.

Magsayo landed a hard right to Russell’s body early in the third round. Russell landed a short left and moved out of Magsayo’s punching range with 30 seconds on the clock in the third round.

Russell made Magsayo miss with numerous power punches in the second round, when Russell went low and slipped a lot of those shots. Russell also landed a straight left hand that backed up Magsayo with approximately 15 seconds to go in the second round.

Magsayo connected with a short right hand on the inside with about a minute to go in the opening round. The challenger landed another right hand about 30 seconds later, but Russell took it well.

Russell dealt with numerous distractions during training camp for his fight with Magsayo, which made Magsayo and his team confident he could pull off an upset.

His father and career-long trainer, Gary Russell Sr., had his left foot amputated last month due to complications from type 2 diabetes. The elder Russell worked his son’s corner Saturday night from a wheelchair on the venue floor, but he missed much of his training camp.

Russell revealed earlier this month that he essentially trained himself for this fight.

Then, during fight week, Russell alluded to an injury that he suffered during camp. He wouldn’t elaborate, but he indicated that it wasn’t something fighters typically deal with while preparing for a fight.

Once he lost Saturday night, he told Gray that the shoulder injury that worsened during the fourth round was the undisclosed injury to which he referred.

In addition to his father’s health issues and his mysterious injury, Russell fought for the first time since he out-pointed another mandatory challenger, Tugstsogt Nyambayar, unanimously in a 12-rounder Showtime televised in February 2020 from PPL Center in Allentown, Pennsylvania.

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