Stars collided in Shanghai on Sunday when Roger Federer went to the NBA champion Golden State Warriors' preseason game at the Mercedes-Benz Arena.

Of course, the 19-time Grand Slam champion was invited into the locker room. He also got a picture with Kevin Durant...

???? in ???????? Shanghai

A post shared by Roger Federer (@rogerfederer) on

...And created a funny one with one with Hall of Famer Yao Ming. Yao owns the Shanghai Sharks, the team he played for from 1997 until 2002, when he was the first overall pick in the NBA draft. 

Federer, to be clear, it not a small guy—the ATP lists him at 6'1". Yao, though, was listed as 7'6" and 310 pounds in his playing days. The Warriors won the game 142-110 over the Minnesota Timberwolves. 

Federer has really been making the rounds in Shanghai, from kicking off a party with Moet Chandon... riding the subway.

Federer, the No. 2 seed this week, kicks off his Shanghai ATP Masters campaign against the winner of Jordan Thompson and Diego Schwartzman.