Social media star turned boxer KSI admits that his most recent exhibition win was tarnished.

On Saturday night at the OVO Arena Wembley, KSI had his biggest test in the form of undefeated pro Joe Fournier (9-0, 9 KOs), who is 40-years-old and went up against very limited competition in his pro run.

During the second round, KSI rocked Fournier, but then landed an elbow to the jaw that knocked Fournier out. The referee missed the illegal blow and waved off the fight with a with badly hurt Fournier on the mat. KSI was announced the winner via knockout at 1:25 of round two.

KSI claims it was a punch and then a forearm that connected on Fournier - which doesn't exactly gel with video footage of the knockout. Fournier was in trouble, but there is disputing that an elbow put him away.

“I worked very hard for this fight and had an intense and grueling camp,” KSI wrote on Twitter. “There’s no better feeling than being in that ring and having my hand raised in front of my loyal and amazing fans who I appreciate so much.

“Unfortunately the victory which was inevitable no matter what, is tarnished and I hate that. It sucks! After landing my overhand he was pretty much out on his feet and I went for a short right hook as Joe clinched me and fell into me. I landed that hook and my glove made contact but appears to have been followed by unintentional contact with my forearm. I’m gutted that it’s not as clean a win as I wanted and it feels like it diminishes my hard work with my trainers.

“Either way I hope you enjoyed the show and appreciate the support. Sorry to all the fans disappointed with it. No one is more so than me.”

Youtube star turned boxer, Jake Paul, took to social media to call KSI a liar for not admitting that an illegal elbow rocked the jaw of Fournier.

Paul wants the British Boxing Board of Control (BBBofC), not an independent governing body like the PBA (Professional Boxing Association), to oversee the KSI events.

“Why you lying still?” Paul wrote. “No part of your glove made contact with Joe’s face on that elbow. That was not a hook. That was straight up a right elbow to the jawbone. Good form but wrong sport.

“Your whole promotion is [a] sham. Bad look for the sport of boxing. Your ‘commission’ PBA should hold itself to a higher standard. I hope England Boxing starts to oversee this product and makes it safer for everyone.”