He beat up of Bruno Silva in the clinch in round 3 of their fight. Of the fighters who Alex has fought I think Bruno might have the closest style to Roundtree's. He throws looping punches usually in combination, often finishing with a kick. Bruno Silva might not have quite the power of Roundtree, and Roundtree probably doesn't have the durability of Bruno, but Bruno touched Alex a few times. There was a good combi in the first that caused Alex to clinch, and then in the 3rd, Alex roughed up Bruno with knees and punches.
Alex also lost his last kickboxing match after losing a point for excessive clinching. So it isn't something he isn't known for.
He has KO losses in his kickboxing career as well. Kyshenko beat him up against the ropes for a standing stoppage where he was clearly out on his feet. Wilnis knocked him down with body shots twice and finished him with a leg kick to get a KO victory. Those liver punches were gnarly, too. The second one was so hard it turned the lights off to the whole stadium. Seriously, the lights went out when he was dropped the second time, and he got a bunch of extra time to recover while they sorted that out, the fight might have been stopped then if there weren't technical difficulties. And then he got crushed by a leg kick after getting his head and body battered while was trying to shell up. Wilnis fought Alex 3 times, with Alex only winning the 3rd match. Their first match, where Wilnis stopped Alex, was at It's Showtime 60. It's worth watching.
The reason why Adesanya's second loss to Alex was talked about so much wasn't just because it was Izzy's last kickboxing match. Alex was the only guy to top Izzy. All of Adesany's other losses were decisions. Alex already had a stoppage loss before he fought Izzy. And he was slept by Izzy in MMA. So, yeah, there's evidence that he's not punch proof.
