Alistair Overeem has fought a who’s-who of combat sports throughout his illustrious career.

The former Strikeforce heavyweight champion and K-1 world grand prix champ is one of a select few fighters to ever hold titles in both kickboxing and MMA at the same time.

Speaking on the “Grange TV” podcast, Overeem (45-18 MMA, 10-7 UFC) said of all the fighters he’s competed against, two names stick out: former K-1 heavyweight champion Badr Hari and former UFC heavyweight champ Fabricio Werdum.

Overeem fought Hari twice. He knocked him out in the first round in 2008 at Dynamite, an annual kickboxing and MMA event held by K-1 and DREAM. The second time, a year later in the K-1 world grand prix semifinals, Hari got his revenge and took out Overeem in Round 1.

“I would say Badr Hari was a rival in K-1,” Overeem said. “So I beat him, and that was actually my entry into the K-1. Then he beat me back, which was very exciting because it was a rematch. We were in the finals. He finished his guy really quick, then I still had to fight. He finished his opponent in one minute, and then I still had to fight my first fight. But I knew I was going to fight a fresh Badr in my second.

“So what happens? I beat my opponent, Ewerton Teixeira, in under a minute, so I beat him quicker than Badr beat his guy. So it was a real buildup towards that moment. And then I lost to Badr in – I don’t know, it was the first round or something. So that was a big rivalry. I remember it was very live all over the world, a lot of fans back and forth.”

Overeem fought Werdum three times. The first time was in 2006, in the PRIDE heavyweight grand prix opening round, where Werdum submitted Overeem with a second-round kimura. The second time was during the Strikeforce grand prix quarterfinals in 2011, where Overeem defeated Werdum by unanimous decision. Finally, at UFC 213 in 2017, Overeem prevailed in the trilogy with a majority decision.

“Werdum and I had a rivalry, which was interesting,” Overeem said. “(We had) three fights over many years – 2006 was the first time, 2011 the second, and 2017 the third fight. He’s also a fighter that’s grown tremendously throughout his career. I remember in the beginning, he was just a grappler, a BJJ guy. But later, in the second fight, all of a sudden he had striking, as well. I outgrappled him, but he outstruck me, which was also interesting. And in the first fight, it was kind of like whatever. He grew a lot as a fighter, but I kind of knew how to handle him. If you’ve been watching someone for, what is it, 11 years, 12 years? You kind of know what to expect.”