When you're the reigning Oscar Best Actress, you undoubtedly have your choice of U.S. Open dates. For Saturday night's women's championship match, Emma Stone took full advantage of this perk and attended the event with an extra-special guest: tennis champ Billie Jean King, whom Stone portrays in the upcoming film Battle of the Sexes.

Stone and King were spotted cheering, laughing, and taking photos of each other in the stands of Arthur Ashe Stadium on Saturday as 24-year-old Sloane Stephens brought home the trophy, defeating Madison Keys. This year's U.S. Open, which took place at the Billie Jean King National Tennis Center in New York City, also marked the 50th anniversary of King's winning the women's singles, women's doubles, and mixed doubles championships at the 1967 U.S. Open.

In a court side interview with ESPN during the match, King and Stone heaped praise on each other. When asked what it was like to watch Stone bring her story to life onscreen, King, 73, said, "First of all, to be played by Emma—I was in shock, amazed, thankful, and blessed." She continued, "You know, she is the number one actor in the world right now, and just to listen to her and how eloquent and how much work she did; she works hard, but she's also really smart and really intelligent." King added, "It's been quite amazing spending time with Emma now, and I'm still learning, but she's amazing, how she does her processing."

Stone, 28, was equally admiring of her offscreen counterpart: "I think that my favorite quality in Billie Jean—and maybe many people feel this way—is that she's a true humanitarian. She's someone who listens to everybody's story, she asks so many questions," she said. "And sitting here at the U.S. Open next to her, hearing her commentary on the sport, is just—she's so brilliant in so many ways."

Last month, Stone revealed to Entertainment Weekly that her approach to preparing for the role did not include spending too much time with the tennis pro IRL. "At first, I was very excited to get to meet and to know Billie Jean, but I also really quickly realized that I was going to need to distance myself the slightest bit," Stone said. "She was so warm and open with me, but she's also so fully formed now and has a good 45 years of reflection on this time in her life. I was so desperate not to let her down and was so nervous about it, I sort of tried to get to know her through old footage more than asking her questions."

She added, "It was a tricky balance because as much as I wanted to be best friends forever with her because she's the warmest and kindest and funniest individual, I was like, if I get too close, I think I'm going to really be afraid."

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