AceShowbiz - Rebel Wilson is showing some support to Serena Williams. In a gushing social media post, the "Senior Year" star says seeing the tennis star play in the U.S. Open is a "spectacular way to end the summer."

The 42-year-old Australian actress called Serena, who is retiring after the tournament after taking home 23 Grand Slam titles, "a legend" following seeing her play with her girlfriend, Ramona Agruma. She wrote on Instagram after watching Serena on Monday, August 29, "The @usopen is such a spectacular way to end the Summer."

"Was so great to see Serena play tonight! What a legend!" Rebel continued. She went on to say, "Looking forward to more quality matches and it was great to also celebrate @ustafoundation and the great charitable work that they do with under-resourced kids. #USOpen #BeOpen"

In the match, Serena beat Danka Kovinic in straight sets, which was watched by a star-studded crowd including Hugh Jackman, Spike Lee, President Bill Clinton, Queen Latifah, Matt Damon, Anthony Anderson and Mike Tyson.

After securing victory, Serena called it "extremely difficult" to leave her beloved sport behind. She said, "It's extremely difficult still because I absolutely love being out there. The more tournaments I play, I feel like the more I can belong out there. That's a tough feeling to have, and to leave knowing the more you do it, the more you can shine. But it's time for me, you know, to evolve to the next thing. I think it's important because there's so many other things that I want to do."

Serena, who has four-year-old daughter Alexis Olympia with her husband, tech entrepreneur Alexis Ohanian, also commented on the "overwhelming" reaction from the crowd. She said, "When I walked out, the reception was really overwhelming. It was loud and I could feel it in my chest. It was a really good feeling. It's a feeling I'll never forget. It meant a lot to me."