Chael Sonnen has shared the Octagon with some massive punchers – but his hardest-hitting opponent may come as a surprise to many.During a 49-fight (31-17-1) professional MMA career stretching back to 1997, Sonnen locked horns with a who’s who of future and current Hall of Famers, including Jon Jones, Anderson Silva, and Fedor Emelianenko.GettySonnen has taken some big shots from heavy handed foes like Jones[/caption]Yet Sonnen insists that nobody had heavier hands than Demian ‘The Head Juicer’ Maia.The Brazilian MMA star isn’t known for his striking skills or his power.Rather, Maia’s legacy is defined by his elite Brazilian Jiu-Jitsu skills.Of his 28 career wins (28-11), Maia has only finished one fight inside the distance with punches.But when he duked it out with Sonnen in February 2009 at UFC 95, he caught ‘The Bad Guy’ with a backhand that left him in excruciating pain.“The hardest I have ever been hit was by Demian Maia,” said Sonnen during a video on his YouTube channel.“Demian Maia backhanded me. He was in guard on the bottom, where you can’t even generate much power.“He reaches over like he is going to go in for a kamura, and then he brings a backhand across and it smacks me in the face.“I remember hearing a click. I remember my jaw had been hit so hard that I could hear it click.“And that is when the fight was over. That was the hardest I have ever been hit in terms of pain.”GettyIt was grappler Maia who caught him with the biggest punch, though[/caption]Moments after the clubbing blow landed, Maia locked in a triangle choke to force the tap in the opening stanza.In the years that followed, both men went on to challenge for UFC titles in two separate weight classes.However, neither was able to get their hands on gold.Sonnen had two cracks at Silva’s middleweight title and a controversial shot at Jones’ light heavyweight crown one fight after losing his rematch to ‘The Spider’.The first time he fought Silva, he led by 40-36, 40-35, and 40-34 heading into the fifth and final round, only to be caught in a Hail Mary triangle choke with less than two minutes left on the clock.In his previous title defence, Silva had defeated Maia via unanimous decision.Sonnen challenged for UFC gold three times, and despite coming desperately close against Silva, he never became a championGETTYBut after dropping down to welterweight, Maia mounted another attempt at a title shot. This time, he was bested by Tyron Woodley.