The tennis GOAT is chilling with her friend, reality show GOAT.

Serena Williams has a lot of famous best friends, with Kim Kardashian being among them. And the two shared some happy bestie time Monday night, as Serena preps for her US Open quarterfinal against sister Venus Williams.

Sipping & spilling the tea tonight with Serena ☕️

A photo posted by Kim Kardashian West (@kimkardashian) on Sep 7, 2015 at 6:30pm PDT

Forget a calendar Grand Slam. Serena having casual tea time with Kim further seals her being the G.O.A.T.