Britain's KSI edged American Logan Paul in a cruiserweight boxing rematch of YouTube celebrity stars Saturday that proved a hit with audiences and could help such fighters capture mainstream respect.

KSI, a 26-year-old London internet personality and rapper also known as Olajide Olatunji, was declared a split decision winner by judges.

Two scored KSI a winner by 57-54 and 56-55 while Paul was seen a 56-55 winner by the third judge at the Los Angeles showdown, a star-studded affair with Justin Bieber, Wiz Khalifa and Mike Tyson among celebrities in the crowd.

The first fight, hyped as the biggest event in internet history, ended in a majority draw. It was contested under amateur rules in August 2018 at Manchester, England, but the rematch was a professional debut of six three-minute rounds.

Paul, who said he was ill all day before the bout, had two points deducted in the fourth round for punching KSI while he was on the canvas.

After the fight, Paul said he didn't feel as if he was defeated.

"You'll see me in the squared circle again," Paul vowed. "I'll be back."

But KSI dismissed any thought of a third fight against Paul.

"It is done," he said. "I'm on to the next thing."

Fight telecaster DAZN's executive vice president for North America, Joseph Markowski, told AFP the fight had been a major triumph for the streaming service.

"Saturday night was a big success," he said. "The KSI versus Logan Paul event generated a significant boost in subscriptions, caught the attention of mainstream media and introduced the sport of boxing to a completely new audience.

"Those were our goals at the outset and we are very pleased with the results."

Logan Paul, right, delivers a punch to KSI in their cruiserweight fight Saturday at Los Angeles
Logan Paul, right, delivers a punch to KSI in their cruiserweight fight Saturday at Los Angeles GETTY IMAGES NORTH AMERICA / Jayne Kamin-Oncea

Mexican-American veteran pro fighter Abner Mares -- a former world champion at bantamweight, super bantamweight and featherweight -- ripped the online video celebrity bout.

"When did "BOXING" become such a JOKE?? #KSILoganPaul2," Mares tweeted.

"Listen everybody's got their own thoughts and opinion about this fight last night, but me as a real professional boxer that has sacrifice so much to get to a certain level and get paid what I deserved is a slap in the face in so many ways.

"Nothing to do with the network or how it was promoted because if you ask me yes it's smart on their end financially, but I saw so many illegal punches that could've damage a persons life and to see how much they got paid for a 6 round fight and to see real pros be the under cards," he added.

"I know a lot of y'all said it was entertaining but so are the fights between two crackheads in the street. I'm just speaking as a real pro fighter but then again I have to remember that we live in a world that is upside down now days."

Former European super welterweight champion Ryan Rhodes of Britain tweeted: "So now KSIvsLoganPaul2 is over who's up for @justinbieber v @ZacEfron for the Disney title?"

Britain's Amir Khan, a former light-welterweight world champion, praised the bout, saying: "2 novice fighters put on a good fight tonight. Well done to my friend @KSIOlajidebt and unlucky @LoganPaul. A 3rd fight wouldn't surprise me."

Britain's Audley Harrison, a 2000 Sydney Olympic super-heavyweight gold medalist and former European heavyeight champion, saw improvement from the fighters since the first bout.

"Now I know the boxing purist may poo poo some of the boxing fundamentals on show, but both fighters were much improved over last year & overall did not discredited boxing - for their debut it was," Harrison tweeted.