Lopez (16-0) added the three titles held by Lomachenko (15-2) to the belt he won last year to become the undisputed 135 champion.
Lopez was favored 119-109, 117-111 and 116-112 on the ring scorecards in a fight held without fans at the MGM Grand Conference Center. The Associated Press had Lopez winning 117-111.
Lopez turned out to be faster and stronger than 32-year-old Lomachenko, who won two Olympic gold medals as an amateur and was considered one of the best pound-for-pound fighters as a pro. Surprisingly, he was also the best boxer and proved that he can close the show by bloodying Lomachenko’s eye in the 12th round.
“I had to dig deep, man,” Lopez said. “I’m a fighter, I have to dig deep.”
Lomachenko, usually a slow starter, was too slow this time around as he gave early laps as he tried to figure out Lopez’s style. By the time the fight got competitive in the eighth round, he was too far behind to return.
“He was laid off for 14 months,” Lopez said. “I knew it would take a long time for him to catch up.
Lomachenko, who has lost just once in nearly 400 amateur fights and had only one loss as a pro, thought he was doing better than the scorecards shown.
“I certainly don’t agree with the scorecards,” he said.
The fight was the biggest since the start of the pandemic and would have been a pay-per-view event under normal circumstances. But without fans, it was televised on ESPN, giving boxing a bigger showcase than it otherwise would have been.
Lopez was told by his dad in the corner before lap 12 that he was in the lead and was not risking anything. But he came out strong and beat Lomachenko with a punch.
“I didn’t know if they had it on the scorecards or not,” Lopez said.
Lopez became the youngest fighter to become a four-belt champion in just his second title fight. He had sought the fight against Lomachenko, angering the Ukrainian with his brash tactics.