Serena Williams Beats Sister Venus at US Open: Celebrities Watch and React!

Serena Williams of the United States celebrates after defeating Venus Williams of the United States in their Women's Singles Quarterfinals match on Day Nine of the 2015 U.S. Open at the USTA Billie Jean King National Tennis Center on September 8, 2015 Credit: Mike Stobe/Getty Images

Sisterly slam! Serena Williams inched closer to a Grand Slam title on Tuesday, Sept. 8, after beating her sister Venus Williams in the quarterfinals of the US Open at Arthur Ashe Stadium in NYC.

Serena, 33, the top-ranked female tennis player in the world, defeated her big sis after three sets, 6 to 2, 1 to 6, 6 to 3, and continued her bid for a Grand Slam. Following her sibling's win, a proud Venus gave Serena a sweet hug and said, "So happy for you."

Speaking about her victory later, Serena told reporters (via the Associated Press): "Obviously we are very, very tough competitors on the court, but once the match is over, the second it's done, you know, we're sisters, we're roommates, and we're all that."

With two more wins, Serena will be the first tennis pro in a quarter-century to win all four Grand Slam titles in one season, a feat that was last accomplished in 1988 by Steffi Graf. "That would be huge, not just for me, but for my family, just for what it represents and how hard we have worked and where we come from. So it would be a moment for our family," Venus, 35, told the AP on Tuesday. "But at the same time, if it doesn't happen it's not going to make or break you. We don't have anything to prove. She has nothing to prove. She's really the best ever."

Celebrities including Oprah Winfrey, Kim Kardashian, Anna Wintour, Gigi Hadid, Kendall Jenner, Joe Jonas, and Donald Trump, who was booed by the crowd, filed into the stadium to watch the match in humid NYC on Tuesday night. Other stars — like Hilary Swank, LeBron James, and Gabrielle Union — kept up with the action from home, and reacted to Serena's victory on Twitter.

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