Serbian super star knows how to grab eyeballs even off the tennis court. The World No. 1 took his fitness to an entire new level when he wrestled with retired summon professionals on Monday.

The 32-year-old Serb, who is in Tokyo to play in the Japan Open Tennis Championships, visited a traditional dohyo or a sumo ring to watch the wrestlers during their morning practice before attempting to wrestle, albeit an unsuccessful one, in a bid to win over the hefty heavyweights.

Djokovic tried to push his counterpart as much as he could without practically no results.

“I felt I’m out of shape (for sumo) a little bit … with a few more kilos, I’ll be ready to compete. Probably three times as much as I have right now would be the right measurement for me to compete,” Djokovic joked.

“It’s quite impressive to see also how flexible they are … I didn’t think that they were that flexible considering it’s a heavyweight sport,” he told the ATP website.

“But I see that they are paying a lot of attention to the mobility of their joints … which is of course what allows them to move around as agile as possible at their weight.”

Djokovic, a 16-time Grand Slam winner, may have been unsuccessful in his attempts to defeat the sumo wrestlers, but his moves in the ring impressed his fans online.

“It’s a great experience … one of the most popular sports in Japan. Speaking with my father yesterday on the phone I was telling him that I’m going to have an opportunity to meet sumo wrestlers,” Djokovic said.

“He and I were remembering many years ago when we used to watch Akebono … someone we supported a lot.”

Djokovic plays Australian Alexei Popyrin in the first round on Tuesday.