Nadal, a 22-time grand slam winner, is starting the road back from a hip injury sustained last January with his first appearance at the Brisbane International since 2017.
He hit the ball Thursday at the Queensland Tennis Centre, including a session with world number eight Holger Rune (20) of Denmark.
Rune shared a photo of the joint practice on social media with the caption, "No time for jetlag. Evening practice with @RafaelNadal."
Due to his lack of tour play, Nadal has fallen to number 672 in the world. The Spaniard previously said he expects this to be his final season on tour.
He will appear at the Brisbane tournament, which begins Sunday, as a wildcard. He will be unseeded for the first time since January 2005.