NEW YORK -- Teofimo Lopez promised a first-round knockout and pushed hard to accomplish just that by unloading on George Kambosos, but in a stunner, the opening round to their fight Saturday night ended with the champion on the canvas.
Turns out, the knockdown wasn't a fluke but a harbinger of what was to come in one of the best action fights of 2021. Kambosos, the underdog from Australia, survived a 10th-round knockdown to score a split decision victory over Lopez in a major upset to claim the WBO, WBA, IBF and WBC franchise lightweight championship at Hulu Theater at Madison Square Garden.
One judge scored 114-113 for Lopez, with the other two judges scoring for Kambosos, 115-112 and 115-111.
"I believed in myself, I backed myself," said Kambosos, 28. "I thought, 'I'm going to hit him hard and put him down,' and the fight changed off that. ... I'm an unbelievable boxer. I can't believe how good I boxed."
Fans surely couldn't believe the fight finally happened. The bout was set for June 19 in Miami before Lopez contracted COVID-19, spiraling the event into a quagmire of legal threats in a soap opera that was wild even by boxing standards.
Triller won the rights to the fight at February's purse bid with a commitment of $6.018 million, but the IBF found the company in default and awarded the bout to Matchroom Boxing's Eddie Hearn.
After eight date changes along with numerous stops and starts to training camp, a bout that was viewed as a mismatch -- a routine title defense for a rising star -- grew into an event of intrigue.
And the fight delivered beyond anyone's wildest expectations. Following the opening round that concluded with Lopez on the deck, the pair exchanged in a firefight for the duration of the evening.
Lopez (16-1, 12 KOs), of Brooklyn, New York, found his mark with plenty of overhand rights, but so did Kambosos. Surprisingly, Kambosos was the cleaner puncher. He also was the fresher fighter.
Kambosos (20-0, 10 KOs) buckled Lopez at the tail end of Round 4 and took control of the bout. He worked the jab and followed with looping rights that marked up Lopez's face. By the time the decision was rendered, Lopez's left eye was bleeding profusely, and so was his nose. He also had a gash under his right eye.
Both fighters were transported to a hospital after the bout -- Lopez for two separate cuts over both eyes and Kambosos for dehydration.
"I don't care what anybody says," Lopez said, "I won tonight. At the end of the day, I've been here, I've done it. Look, I'm not a sore loser. I take my wins like I take my losses.
"At the end of the day, I'm a true champion. I came out here, I did what I had to do, and I went out there and I did my best. ... This is the takeover. We don't stop. We keep coming."
For Lopez, it was a shocking fall from grace. Just 13 months ago, Lopez upset future Hall of Famer Vasiliy Lomachenko to claim four lightweight titles in a career-defining victory. The landmark win earned Lopez the No. 7 spot in ESPN's pound-for-pound rankings and seemingly set him on the path to superstardom.
Following a careerlong layoff, a battle with COVID-19 and all the chaos that swirled around the rescheduled bout, Lopez appeared lethargic and tired over the final eight rounds Saturday night.
"They've been draining me all the time," Lopez, 24, said of his difficulty to make the 135-pound limit.
Kambosos was ahead on all three scorecards when Lopez floored him with a punishing right hand. The first-time title challenger was on unsteady legs but still fired back as he attempted to regain his balance.
By the time Round 11 rolled around, Kambosos had found his senses and finished strong, sweeping the championship rounds (11 and 12) on one judge's scorecard and splitting those rounds on the other two cards.
"It wasn't a big knockdown," said Kambosos, who entered the bout rated No. 9 by ESPN at 135 pounds. "I wanted to feel the power. [I thought], 'I'm going to punish him for what he just done to me.'"
Both fighters landed career-best purses Saturday night: Lopez earned $3,178,000 and Kambosos $1,527,100.
With the victory, Kambosos is now the top fighter in one of boxing's most stacked divisions. Lightweight is home to Devin Haney, Gervonta Davis, Ryan Garcia and Joseph Diaz Jr.
It might not be home to Lopez any longer. He said he plans to move up to 140 pounds and hopes for a shot at undisputed champion Josh Taylor.
After Saturday's loss, it's unclear where Lopez heads next, but Kambosos' path is far more certain.
"Right now, he's the boss," said his promoter, Lou DiBella. "He earned it tonight. It was a mandatory [title defense]. There's no rematch clause. We're going to do whatever's in [George's] best interests from a business perspective.
"He's going to sit back, take a little time off and enjoy the victory. Then we're going to figure out the biggest fight we can make."