Lomachenko delivered a devastating right hook to the temple that sent the Englishman crashing face first to the canvas just 58 seconds into the fourth round.
Ukrainian boxer Vasiliy Lomachenko seals victory over Jose Pedraza to unify WBO and WBA lightweight belts
Ukraine's Lomachenko, a three-weight world champion who had never before unified two titles in the same class, knocked down Pedraza twice in an explosive 11th round.
WBO super-lightweight champion Maurice Hooker defends title with seventh-round technical knockout of Alex Saucedo
Maurice Hooker was credited with a knockdown when he sent Saucedo reeling into the ropes and when the fight resumed he pummeled the challenger until the referee jumped in
Indian boxer Vijender Singh on Tuesday said his much-awaited fight for the Commonwealth super middleweight title could be held in September after being cancelled earlier this month, but the opponent has not yet been finalised.
Pacquiao said he heard that McGregor was willing to fight him after the Irish mixed martial artist's foray into boxing.
"It will not push through there in Australia. But we are bringing the fight here in the Philippines," Pacquiao said on radio station DZBB, adding negotiations were ongoing.
Vijender, who has not competed since successfully defending his title against Francis Cheka in December 2016, will take on China's Zulpikar Maimaitiali on 5 August.
Eight-time world boxing champion Manny Pacquiao has said he will "think hard" about retiring after his stunning and controversial defeat to unheralded Australian challenger Jeff Horn.
The online ticket sales of Indian boxing star Vijender Singh's showdown with Chinese Zulpikar Maimaitiali in a double title fight in August started on Sunday.
Andrzej Soldra has threatened to stop Vijender Singh in his tracks and inflict the first loss on his record.