By Keith Idec

ATLANTIC CITY – Eleider Alvarez was even more dangerous than many experts expected.

The resilient Colombian contender knocked down Sergey Kovalev three times in the seventh round Saturday night and pulled off an upset by knocking out the Russian knockout artist to win the WBO light heavyweight title. Kovalev was in control of their fight, had battered Alvarez throughout the fourth round and was winning on all three scorecards when Alvarez landed a perfect right hand to the side of Kovalev’s head and knocked him down in the seventh round.

A stunned Kovalev got off the seat of his trunks in time to continue and tried to fight back. Alvarez knocked him down twice more, however, which forced referee David Fields to stop their scheduled 12-round championship match at 2:45 of the seventh round.

A vicious left-right combination knocked down Kovalev the second time and a third trip to the canvas left him in no condition to continue in the main event of HBO’s doubleheader from Hard Rock Hotel & Casino’s Etess Arena.

The 34-year-old Alvarez, who’s based in Quebec, improved to 24-0 and scored the 12th knockout of his career. The 35-year-old Kovalev (32-3-1, 28 KOs), who was listed by several Internet sports books as a 7-1 favorite, lost by technical knockout for the second time in his career and for the second time in his past four fights.

Unlike Kovalev’s controversial TKO defeat to Andre Ward in their rematch in June 2017, there was nothing questionable about this crushing loss.

“As the fight went on I wanted to show that I could stay strong and do good things,” Alvarez said. “His punches were not as hard as they were in the beginning of the fight.”

Kathy Duva, Kovalev’s promoter, said at ringside that there’s a rematch clause in their contracts. Duva couldn’t commit in the immediate aftermath of this devastating defeat to whether the rematch would take place immediately.

“[Kovalev] was way ahead, much like the Ward fight,” Duva said in reference to Kovalev’s first defeat to Ward, a controversial unanimous decision loss in November 2016. “I think Sergey seems to gas out after six rounds. That seemed to be the magic round with Ward, too. He did great for six rounds and then he started to falter. I assume he got tired [Saturday night].”

Judges Carlos Ortiz (58-56), Joseph Pasquale (59-55) and Lynne Carter (59-55) each had Kovalev in front by at least two rounds through the sixth.

The fight and their careers completely changed in the seventh round.

Kovalev landed a hard jab and a right hand early in the seventh round, just after Alvarez clipped Kovalev with a right hand of his own. Later in the seventh, however, Alvarez’s right hand caught an exposed Kovalev to the left side of his head, near his temple.

There was no indication in the previous round that Alvarez was poised to clip Kovalev with that type of punishing shot.

Kovalev cracked Alvarez with an overhand right while they stood in the center of the ring just after the halfway point of the sixth round. An accidental clash of heads also opened a cut beneath Alvarez’s left eye during the sixth round.

Kovalev and Alvarez each landed left hooks during an interesting exchange toward the end of the fifth round.

For the third time in the first four rounds, Alvarez drew a warning from Fields, this time for hitting Kovalev below the belt early in the fourth. Kovalev cracked Alvarez with a perfect overhand right later in the fourth.

Kovalev then connected with a clean combination and another flush right hand in the fourth. Alvarez absorbed all those shots, but the fourth round clearly was the best of their fight for Kovalev to that point.

Alvarez landed a left hook early in the third round. Kovalev came back with a left hook of his own, but Alvarez shook his gloves to indicate it had no effect on him.

Kovalev kept the pressure on his challenger in the third round, which set up a left hook to the body, followed by a left hook to Alvarez’s head.

Alvarez snapped back Kovalev’s head with a jarring jab early in the second round. He also knocked Kovalev off balance with a jab late in the second round.

For the second time in as many rounds, Fields warned Alvarez for fouling as he ushered Alvarez back to his corner once the bell sounded to end the second round.

Kovalev and Alvarez both tried to establish their jabs throughout the first round. Alvarez drew a warning from Fields late in the first round for hitting Kovalev behind his head while they were engaged in a clinch.

Even as Kovalev built on his lead, it was obvious Alvarez was by far the toughest of Kovalev’s three opponents since the former champion was stopped by the undefeated Ward in their rematch 13½ months ago in Las Vegas.

Two bouts before facing Alvarez, Kovalev annihilated Ukraine’s Vyacheslav Shabranskyy to win back the WBO title Ward relinquished when he retired last September. Kovalev knocked down Shabranskyy (19-2, 16 KOs) three times on his way to a second-round technical-knockout victory November 25 in The Theater at Madison Square Garden.

Three months later, Kovalev stopped overmatched former amateur teammate Igor Mikhalkin (21-2, 9 KOs) in the seventh round. That title defense was made March 3 at The Theater.

Marcus Browne (22-0, 16 KOs) was considered as the opponent for Kovalev’s second title defense since regaining the WBO championship. Once Browne’s two arrests for domestic violence incidents were reported, however, Duva instead made a fight against Alvarez.

An eager Alvarez jumped at the chance to fight Kovalev because even though he had been the mandatory challenger for WBC champion Adonis Stevenson for more than two years, he had difficulty securing that title shot.

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