Greatness respects greatness. 

Serena Williams is planning to "evolve" away from tennis after the U.S. Open, and everyone wants a chance to see her make one last run — including her good friend, Tiger Woods. 

Woods was in attendance, sitting in Williams' player box at Arthur Ashe Stadium, for Williams' second-round victory over world No. 2 Anett Kontaveit. 

The ESPN telecast frequently showed Woods in the stands, and though he wasn't knocking in a winning putt, the 15-time major champion broke out his signature fist pump. 

After the match, Woods accompanied Williams, 40, into the locker room and had his arm around her. 

"It was a privilege to watch greatness. Congrats @serenawilliams," Woods tweeted after the match.

In Williams' post-match press conference, the 23-time Grand Slam champion credited Woods, 46, for being a vital part of her farewell tour. 

"He's one of the reasons I'm here, one of the main reasons I'm still playing," she said. "We talked a lot. He was really trying to get me motivated. There are a few people, but we were like, 'OK, we can do this together, you know?'"

Last month when Williams published a first-person essay on Vogue.com that she is planning to "evolve" away from tennis after the U.S. Open, she wrote that she leaned on Woods for advice about how to wind down her career.

"I was talking to Tiger Woods, who’s a friend," she wrote, "and I told him I needed his advice on my tennis career. I said, 'I don’t know what to do: I think I’m over it, but maybe I’m not over it.' He’s Tiger, and he was adamant that I be a beast the same way he is! He said, 'Serena, what if you just gave it two weeks? You don’t have to commit to anything. You just go out on the court every day for two weeks and give it your all and see what happens.'"

And as Williams gives it her all one last time, trying to tie Margaret Court's all-time record of 24 Grand Slam titles, Woods is there to help her go out on top. 

Williams will play Ajla Tomljanović Friday night in the third round. And maybe, there will be another Woods sighting.