Best of the U.S. Open

Serena Williams of the United States hits a forehand against Anastasija Sevastova of Latvia in a women's semi-more

Novak Djokovic of Serbia celebrates match point against John Millman of Australia in a quarter-final match. Jmore

Naomi Osaka of Japan serves against Madison Keys of the United States (not pictured) in a women's semi-final mmore

Madison Keys of the USA reacts after losing a point in the 2nd set to Naomi Osaka of Japan in a women's semi-fmore

Kei Nishikori of Japan wins his quarter-final match against Marin Cilic of Croatia. Danielle Parhizkaran-USA more

Naomi Osaka of Japan celebrates after recording match point against Madison Keys of the USA in a women's semi-more

Novak Djokovic of Serbia talks with the chair umpire after being called for two time violations while serving more

Anastasija Sevastova of Latvia, left, and Serena Williams of the United States, right, shake hands after Willimore

Roger Federer of Switzerland walks off the court after his loss to John Millman of Australia in a round of 16 more

Serena Williams of the United States celebrates match point against Karolina Pliskova of the Czech Republic inmore

Rafael Nadal of Spain serves to Dominic Thiem of Austria in a quarterfinal match on day nine. Robert Deutsch-Umore

Juan Mart n Del Potro of Argentina celebrates after his match against John Isner of the United States in a quamore

Aryna Sabalenka of Belarus serves against Naomi Osaka of Japan in the fourth round on day eight of the US Openmore

Serena Williams of the USA hits to Kaia Kanepi of Estonia in a fourth round match on day seven. Robert Deutschmore

Novak Djokovic of Serbia reacts after a miss to Tennys Sandgren of the USA in a second round match on day fourmore

Roger Federer of Switzerland hits a forehand against Nick Kyrgios of Australia in the third round on day six. more

Serena Williams of the USA after beating Venus Williams of the USA in a third round match. Robert Deutsch-USAmore

Benoit Paire of France reacts after a miss to Roger Federer of Switzerland in a second round match on day fourmore

Sloane Stephens of the USA celebrates her win over Victoria Azarenka of Belarus in a third round match on day more

Novak Djokovic of Serbia copes with the extreme heat while playing Marton Fucsovics of Hungary in a first rounmore

Maria Sharapova of Russia celebrates after winning a point in the first set of a first round match against Patmore

Roger Federer of Switzerland hits to Yoshihito Nishioka of Japan in a first round match. Robert Deutsch-USA TOmore

Eugenie Bouchard of Canada serves against Harmony Tan of France (not pictured) in the first round. Geoff Burkemore

Novak Djokovic of Serbia hits a backhand against Marton Fucsovics of Hungary (not pictured) in the first roundmore

Yuichi Sugita of Japan hits a forehand against Richard Gasquet of France (not pictured) in the first round. Gemore

Angelique Kerber of Germany serves against Margarita Gasparyan of Russia in a first round match. Jerry Lai-USAmore

Roger Federer of Switzerland serves against Yoshihito Nishioka of Japan (not pictured) in the first round. Geomore

Pauline Parmentier of France hits to Madison Keys of the United States in a first round match. Danielle Parhizmore

Serena Williams of the USA hits to Magda Linette of Poland in a first round match. Robert Deutsch-USA TODAY Smore

Simona Halep of Romania smashes her racket on the ground during her loss to Kaia Kanepi of Estonia on day one.more

Kelly Clarkson performs at the opening ceremony of the 2018 U.S. Open. Robert Deutsch-USA TODAY Sports

Andy Murray of Great Britain gives a thumbs-up after a win on day one. Danielle Parhizkaran-USA TODAY Sports

Victoria Azarenka of Belarus reacts after defeating Viktoria Kuzmova of Slovakia in two sets in the first rounmore

Mike Tyson (left), Anna Wintour (middle) and Vera Wang (right) watch the matches on day one. Robert Deutsch-Umore

Venus Williams of the USA hits to Svetlana Kuznetsova of Russia in a first round match. Robert Deutsch-USA TOmore

Kevin Anderson of South Africa celebrates after winning the first set against Ryan Harrison of the United Statmore

Denis Shapovalov of Canada reacts after losing a point against Felix Auger-Aliassime of Canada (not pictured) more

Milos Raonic of Canada waves to the crowd after his match against Carlos Berlocq of Argentina (not pictured) imore