Lomachenko initially thought the fight had been stopped.
Crolla recovered and 11 months later he won the WBA lightweight belt that Lomachenko retained on Friday. "I always need to find a key for his defense".
Campbell could be a potential opponent for Lomachenko as he has earned a mandatory shot at the WBC title now held by Mikey Garcia, who is yet to announce if he will vacate the belt. He will be facing a tough test in Crolla (34-6-3, 13 KOs), however, despite the British boxer being a mandatory challenger.More news: Robert Kraft's Lawyers In Court To Fight Release Of "Rub & Tug" Footage
Crolla, 32, wasn't Lomachenko's first choice as an opponent. Lomachenko wanted to fight IBF champion Richard Commey, but Commey suffered a hand injury. Crolla lost the title to Jorge Linares back in 2016 and lost the rematch as well.
"I've been doing this for well over 50 years, and I've never seen anything like that guy", said Bob Arum, Lomachenko's Hall of Fame promoter.
The Ukrainian delivered a devastating knock-out in the fourth round at the Staples Center in Los Angeles to continue his remarkable legacy as the pound-for-pound star of the sport. 'I feel like I'm in Ukraine here'.More news: Ariana Grande shares brain scan and opens up about PTSD
Lomachenko's profile has grown exponentially in recent years as he headlined at Madison Square Garden, in Macau and other Los Angeles-area venues before his step up to Staples.
Had Lomachenko not taken the Crolla fight, he would have been stripped of one of his belts.
Lomachenko told Sky Sports: "Of course for me, more interest in Mikey Garcia, but if Mikey Garcia can't cut weight, maybe it will be Luke Campbell, maybe we can organise a fight in the UK. That's my goal. I want historic fights", Lomachenko said post-fight.More news: Maple Leafs goalie Frederik Andersen rediscovering his game in playoffs
Karpency got in the ring with a black eye, and his nose was damaged early by Ramírez, the rangy puncher who had just one previous stoppage victory since 2014.