Undefeated middleweight contender Esquiva Falcao, who next month will fight for the vacant IBF world title when he collides with Vincenzo Gualtieri in Germany, detailed a sparring session from this past Wednesday.

Falcao boxed for twelve rounds with the most unlikely of sparring partners, MMA icon Nate Diaz.

Diaz is training for a scheduled boxing match with Youtube star turned boxer, Jake Paul (6-1, 4 KOs).

The contest will be the pro boxing debut for Diaz - with the fight headlining a DAZN pay-per-view event on August 5th.

Their bout was initially scheduled for eight rounds, but now the contest is being changed to a ten rounder.

Paul will have a size advantage, with the agreed upon weight being 185-pounds. Diaz fought at lightweight and welterweight during his long UFC run. Diaz had his final UFC fight in September of last year, when he submitted Tony Ferguson.

Falcao explained that Diaz was gassing during the spar, which forced the Olympic silver medalist to hold back a bit.

“At first I thought he was tired, and in the end it looked like he was dying,” Falcao said, according to MMAFighting.com. “His fighting style is crazy. You look at him and say, ‘Oh, he’s tired,’ and then we started sparring. [Coach] Robert [Garcia] told me in the second round, ‘He’s tired already, hold back a little bit and keep the rhythm so he does at least 10 rounds.’

“I held back and kept boxing, and we did 12 rounds. He was tired, but taking punches and throwing, too. [He] is bad, [he] is bad, but since he’s too heavy — he’s overweight, probably around 220 pounds or more — and I’m the only big guy in the gym, I had to do it. But I liked doing it.”