Teofimo Lopez was left grimacing after being struck by Hafthor Bjornsson as the pair took part in a Body Shot Challenge.
Bjornsson let rip with a brutal body shot which briefly knocked the boxer off-balance but to his credit he somehow managed to stay upright despite the crunching blow.
Lopez's WBA (Super), IBF, WBO, and The Ring belts will all be on the line next month when he takes on one of his toughest challenges yet - his number one mandatory challenger, George Kambosos Jr.
Ahead of the fight, Lopez has been hard at work preparing for the Kambosos encounter.
But it seems he has taken his preparation to a whole new level after he was filmed taking part in a body shot challenge with 'The Mountain'.
In footage posted to Lopez's official Twitter account, the 24-year-old, the unified lightweight champion of the world, can be seen smiling bravely as he braces himself for impact.
The American visibly winces as the shot finds its target before taking a few steps back to catch his breath almost tripping over some weights lying on the floor behind him.
Lopez can then be heard saying: "That was a good one."
Hafthor Bjornsson does the Body Shot Challenge on Teofimo Lopez
Check out the video below:
Ouch.
Earlier this month Eddie Hearn confirmed that Matchroom Boxing has been awarded the rights to Lopez's mandatory defence against Kambosos after the IBF ruled that Triller had defaulted after trying to change the date of the fight yet again.
Lopez, 24, and Devin Haney recently got into a verbal altercation while attending Sandor Martin's upset win over Mikey Garcia last weekend. Haney does not currently have a fight booked but is expected to defend his WBC belt against JoJo Diaz in December.
Hearn, who represents Haney, said talks with Lopez's camp will take place after those fights.
"I had a meeting with Devin earlier," Hearn told DAZN.
"It’s very frustrating at the moment with JoJo Diaz and a whole situation of people not wanting to fight Devin Haney.
"Devin’s always told me Ryan Garcia will never fight me. I didn’t necessarily believe him but I do believe him now.
"I said to him tonight, ‘Teofimo Lopez will fight you.’ He said he won’t. I said, ‘I reckon he will.’ He said, ‘I’m telling you he won’t.’
"And when he turned up tonight, someone shouted something and he went over and they got head-to-head.
"He said, ‘Look, I’m gunna [sic] f— you up.’ I said (to Haney and Lopez), ‘Guys, you are fighting on DAZN, which is great.
"Teo, you are fighting George Kambosos and Devin, you are hopefully fighting JoJo Diaz. It’s the week after each other. Let’s make the fight.'
"And then everybody started up and arguing for about 20 minutes. I said, ‘Guys, can we just get one thing clear to Teo’s dad: We want the fight.’
"He (Lopez Sr.) said, ‘No, we want the fight.’ I said, ‘Well then, let’s stop arguing, get through our fights and get it made.’ I know Devin will fight him and I do believe Teo will fight him.
"I think you will see that fight in spring of next year."
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