Klay Thompson’s fun offseason just got even more interesting. Nope, this isn’t about Thompson going back to China and reliving #ChinaKlay nor is this about him agreeing to endorse a toaster brand.

With just a few days before the NBA regular season kicks in, Thompson found himself enmeshed in a sporting challenge against a sports icon in the form of Roger Federer. Yes, the great, walking legend, tennis superstar, Roger Federer.

When the Golden State Warriors made a trip to China for a preseason game against the Minnesota Timberwolves on Oct. 5, Federer, who was then preparing for the 2017 Shanghai Masters, met the defending NBA champs. And according to The Athletic’s Anthony Slater, Steve Kerr told him the following conversation between Thompson and the 19-time Grand Slam singles champion.

Federer got a whiff of Slater’s tweet and sort of challenged Thompson to a game of ping-pong.

Ping-pong is neither Federer nor Thompson’s cup of tea, but since it still counts as a racquet sport, we’ll label the Swiss as the favorite in this matchup. Thompson isn’t backing down, however.

Federer just won the Shanghai Masters Sunday by beating Rafael Nadal in the title match, so maybe he’ll be able to make a quick trip to Oakland and set up this unlikely showdown between two renowned athletes.