NEW YORK - After numerous starts, stops, delays and venue changes, the lightweight title bout between multi-belt champion Teofimo Lopez and George Kambosos Jr. took place at Madison Square Garden’s Hulu Theater, and it was worth the wait, as both battled through 12 rounds of drama and momentum swings before Kambosos handed Lopez his first loss via split decision in one of the biggest upsets of 2021.

“You don’t believe in yourself, you don’t get this far,” said Kambosos. “I’m the emperor.”

“You’re a helluva fighter, but I won that fight,” said Lopez, who was booed by the hometown crowd. “I don’t think it was a close fight at all.”

Scores were 115-111, 115-112, 113-114 for Sydney’s Kambosos, now 20-0 with 10 KOs. Lopez falls to 16-1, with 12 KOs. Kambosos now holds the WBA, WBO, IBF, WBC franchise and The Ring belts at 135 pounds.

Lopez went swinging for the fences as soon as the bout began, coming up empty but making a statement in the process. Kambosos tried to get his offense in gear, and as the crowd chanted for Lopez, he was able to fire jabs off at the champion, who walked through them in search of the finishing blows. Soon, he had Kambosos in trouble, but a quick counter put Lopez on the deck. Seemingly unhurt, Lopez rose quickly, but nearly got tagged again as the bell sounded.

As round two commenced, Lopez was on the offensive again, albeit in a more measured fashion as he dug to the body before moving upstairs. Surprisingly, Kambosos was holding his own when the exchanges got heated, but it remained to be seen if that would cause Lopez to lose focus as the fight progressed.

Kambosos had a solid third round when it came to volume, but the harder shots still belonged to Lopez, who froze the challenger on a few occasions. The Aussie made sure to get out of the way of Lopez’ bombs in the fourth, though, and it was clear his confidence was growing as he now forced the champion into a fight he might have expected to be over by now.

Lopez slowed the pace down in the fifth, only to get outworked by the challenger, and that was the case in the sixth as well, as Kambosos appeared to extend his lead heading into the second half of the fight.

The crowd fell nearly quiet at times in round seven, with Lopez unable to swing momentum back to his side and Kambosos coolly boxing. A couple hard body shots by Lopez did get Kambosos’ attention, but “Ferocious” got his respect back in the midst of an exchange just before the bell.

The wear of the fight was showing on the face of Lopez, and in the eighth round it also showed his frustration. The Brooklynite did surge at the end of the frame, though, possibly stealing the round as he chased Kambosos.

Lopez had a good run in the ninth as he landed a series of right hands, but the assault ended with a left hook by Kambosos that seemingly surprised Lopez, who nonetheless was still in the fight and making a late charge.

In the tenth, a right hand dropped Kambosos, who seemed more frustrated than hurt, but Lopez went after the finish with a fury until it was clear that the now bloodied Aussie was going to make it out of the round.

In the midst of a close 11th round, referee Harvey Dock halted the action to have the doctor check the cut over Lopez’ left eye, and once the bout was cleared to continue, it was Kambosos doing the better work to possibly earn the frame.

And with the fight possibly up for grabs, the two battlers fought on nearly even terms, each having their moments before the final bell sounded.