Tiger Woods celebrates Rafael Nadal's win with fist pumps

Tiger Woods was fist-pumping and upper-cutting. And he wasn’t even on a golf course.

Woods and his family were in the stands at the U.S. Open on Monday night cheering on friend Rafael Nadal. Chasing his fourth U.S. Open crown, Nadal beat 2014 U.S. Open champ Marin Cilic, 6-3, 3-6, 6-1, 6-2 in the fourth round to advance to the quarterfinals.

Following the match, Nadal was asked what it’s like to compete knowing Woods is in the stands.

“To play in front of Tiger is a very special thing,” Nadal said. “I’ve always said that I don’t have idols, but if I did, I would have to say that one idol is him.”

Nadal acknowledged he wasn't aware of Tiger during the match but appreciated his support.

"It means a lot to me to have him supporting," Nadal said. "As I said, he's an amazing inspiration, all the things that he accomplish on the sport, the way that he managed to keep fighting that hard ...

"Have him supporting and be able to be in touch with him very often for me is something that I am super happy -- and I hope one day we can play golf and tennis together."

Here’s how Woods celebrated …

And here is Nadal sharing his thoughts on Woods, with Woods listening in ...