British heavyweight Moses Itauma pushed Filip Hrgovic off the stage before the Croat slapped him as chaos erupted at the weigh-in for Saturday’s world-title bout.

The pair will fight for the vacant IBF heavyweight title at London’s O2 Arena, with Itauma bidding to become the second-youngest heavyweight champion in history.

The 21-year-old had refused to engage with Hrgovic’s attempts to rile him during fight week but was in a fierce mood as the pair exchanged expletives during a charged face-off.

As Hrgovic turned to pose for photographs, Itauma shoved him in the back, sending the 34-year-old off the stage.

Hrgovic climbed back up, reached through security and slapped the Chatham fighter in the face before members of both teams became involved as security separated them.

“He pushed me first so I just gave it back. He started it,” Hrgovic said, before breaking off from the interview to stare down Itauma.

Earlier in the week, Itauma said Hrgovic – who has repeatedly labelled him a “kid” – was beginning to get under his skin.

“I don’t know, I just lost it a little bit. I had a little itch and I had to scratch it,” Itauma said.

Before the fracas, an in-shape Hrgovic had weighed in at his lightest in seven years – 16st 12lb (107kg), 12 pounds lighter than for his victory over Dave Allen in May.

Itauma, who would also become the second-youngest world champion from Britain if he wins, weighed 17st 4lb (110kg), the same as for his victory over Jermaine Franklin in March.

Friday’s ceremonial weigh-in took place at London’s Spitalfields Market, with the official weigh-in held behind closed doors earlier in the day.

Several hundred people gathered around the food stalls and coffee kiosks for the event, with Itauma walking through the crowd to loud cheers.

He was smiling as he made his way through the market, where some had come specifically for the weigh-in while others were simply passing through and stopped to see what the fuss was about.

Itauma has the unbeaten record, knockout power and reputation as one of boxing’s brightest young talents, but is still building his profile outside the sport.

Sometimes, though, it is what happens outside the ring that gets people talking.

The incident did not appear premeditated, with Itauma looking irritated by what Hrgovic was saying before the shove.

“He wants to stamp his authority and I think that’s what he was doing there – stamping his authority before he gets in the ring,” promoter Frank Warren said.

“He’s showing he’s not fazed by what Filip brings with his experience and sterling amateur background. He’s up for this, alight and on fire.”