Richard Gasquet of France falls during his match against Stan Wawrinka of Switzerland at the Wimbledon Tennis Championships in London, July 8, 2015. REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY

Novak Djokovic of Serbia reacts during his match against Marin Cilic of Croatia at the Wimbledon Tennis Championships in London, July 8, 2015. REUTERS/Suzanne Plunkett 

Richard Gasquet of France falls to the floor after winning his match against Stan Wawrinka of Switzerland at the Wimbledon Tennis Championships in London, July 8, 2015. REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY 

Spectators watch on Court 1 at the Wimbledon Tennis Championships in London, July 8, 2015. REUTERS/Toby Melville 

A line judge gets hit by a shot from Novak Djokovic of Serbia as Marin Cilic of Croatia misses at the Wimbledon Tennis Championships in London, July 8, 2015. REUTERS/Henry Browne

Serena Williams of the U.S.A. celebrates after winning her match against Victoria Azarenka of Belarus at the Wimbledon Tennis Championships in London, July 7, 2015. REUTERS/Toby Melville TPX IMAGES OF THE DAY

Victoria Azarenka of Belarus reacts during her match against Serena Williams of the U.S.A. at the Wimbledon Tennis Championships in London, July 7, 2015. REUTERS/Toby Melville TPX IMAGES OF THE DAY

Line Judges on Court 1 at the Wimbledon Tennis Championships in London, July 7, 2015. REUTERS/Suzanne Plunkett 

Maria Sharapova of Russia reacts during her match against Coco Vandeweghe of the U.S.A. at the Wimbledon Tennis Championships in London, July 7, 2015. REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY

Garbine Muguruza of Spain celebrates after winning her match against Timea Bacsinszky of Switzerland at the Wimbledon Tennis Championships in London, July 7, 2015. REUTERS/Henry Browne TPX IMAGES OF THE DAY

A security guard during a rain delay on Centre Court at the Wimbledon Tennis Championships in London, July 7, 2015. Picture taken with a fish eye lens REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY

Novak Djokovic of Serbia embraces Kevin Anderson of South Africa after winning their match at the Wimbledon Tennis Championships in London, July 7, 2015. REUTERS/Suzanne Plunkett

Groundstaff watch the math between Kevin Anderson of South Africa and Novak Djokovic of Serbia at the Wimbledon Tennis Championships in London, July 7, 2015. REUTERS/Suzanne Plunkett 

Serena Williams of the U.S.A. lunges for a ball during her match against Victoria Azarenka of Belarus at the Wimbledon Tennis Championships in London, July 7, 2015. REUTERS/Stefan Wermuth

Novak Djokovic of Serbia celebrates after winning the second set during his match against Kevin Anderson of South Africa at the Wimbledon Tennis Championships in London, July 6, 2015. REUTERS/Suzanne Plunkett TPX IMAGES OF THE DAY 

Timea Bacsinszky of Switzerland celebrates after winning her match against Monica Niculescu of Romania at the Wimbledon Tennis Championships in London, July 6, 2015. REUTERS/Stefan Wermuth 

Richard Gasquet of France smashes his racket after losing the third set during his match against Nick Kyrgios of Australia at the Wimbledon Tennis Championships in London, July 6, 2015. REUTERS/Henry Browne 

Andy Murray of Britain celebrates after winning the first set of his match against Ivo Karlovic of Croatia at the Wimbledon Tennis Championships in London, July 6, 2015. REUTERS/Toby Melville

Maria Sharapova of Russia serves during her match against Irina-Camelia Begu of Romania at the Wimbledon Tennis Championships in London, July 3, 2015. REUTERS/Toby Melville

Jelena Jankovic of Serbia celebrates after winning her match against Petra Kvitova of the Czech Republic at the Wimbledon Tennis Championships in London, July 4, 2015. REUTERS/Henry Browne TPX IMAGES OF THE DAY

Aleksandra Krunic of Serbia hits a shot through her legs during her match against Venus Williams of the U.S.A. at the Wimbledon Tennis Championships in London, July 3, 2015. REUTERS/Stefan Wermuth

Serena Williams of the U.S.A. reacts during her match against Heather Watson of Britain at the Wimbledon Tennis Championships in London, July 3, 2015. REUTERS/Stefan Wermuth 

Andy Murray of Britain's wedding ring is tied into his shoe laces during his match against Ivo Karlovic of Croatia at the Wimbledon Tennis Championships in London, July 6, 2015. REUTERS/Toby Melville

Police officers observe a national minute's silence for victim's of the attacks in Tunisia a week ago at the Wimbledon Tennis Championships in London, July 3, 2015. REUTERS/Suzanne Plunkett

A spectator takes a selfie with Lucie Safarova of the Czech Republic after she won her match against Sloane Stephens of the U.S.A. at the Wimbledon Tennis Championships in London, July 3, 2015. REUTERS/Stefan Wermuth

Dustin Brown of Germany celebrates after winning his match against Rafael Nadal of Spain at the Wimbledon Tennis Championships in London, July 2, 2015. REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY

Gilles Simon (R) of France embraces Gael Monfils of France after defeating him in their match at the Wimbledon Tennis Championships in London, July 4, 2015. REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY

Jo-Wilfried Tsonga of France slips during his match against Albert Ramos-Vinolas of Spain at the Wimbledon Tennis Championships in London, July 2, 2015. REUTERS/Henry Browne

Spectator stands on a mobility scooter to watch Court 16 at the Wimbledon Tennis Championships in London, July 2, 2015. REUTERS/Suzanne Plunkett

Andy Murray of Britain reacts during his match against Robin Haase of the Netherlands at the Wimbledon Tennis Championships in London, July 2, 2015. REUTERS/Henry Browne

Lleyton Hewitt of Australia dives for the ball during his match against Jarkko Nieminen of Finland at the Wimbledon Tennis Championships in London, June 29, 2015. REUTERS/Stefan Wermuth 

Yulia Putintseva of Kazakhstan gestures during her match against Venus Williams of the U.S.A. at the Wimbledon Tennis Championships in London, July 1, 2015. REUTERS/Henry Browne 

Roger Federer of Switzerland hits a shot during his match against Sam Querrey of the U.S.A. at the Wimbledon Tennis Championships in London, July 2, 2015. REUTERS/Stefan Wermuth

Serena Williams of the U.S.A. reacts after missing a point during her match against Timea Babos of Hungary at the Wimbledon Tennis Championships in London, July 1, 2015. REUTERS/Toby Melville TPX IMAGES OF THE DAY

Kei Nishikori of Japan (L) waits to recieve a serve during his match against Simone Bolelli of Italy at the Wimbledon Tennis Championships in London, June 29, 2015. REUTERS/Toby Melville TPX IMAGES OF THE DAY 

Nick Kyrgios of Australia hugs a ball boy during his match against Richard Gasquet of France at the Wimbledon Tennis Championships in London, July 6, 2015. REUTERS/Henry Browne 

Heather Watson of Britain keeps her eye on the ball during her match against Daniela Hantuchova of Slovakia at the Wimbledon Tennis Championships in London, July 1, 2015. REUTERS/Suzanne Plunkett

Caroline Wozniacki of Denmark hits a shot during her match against Denisa Allertova of the Czech Republic at the Wimbledon Tennis Championships in London, July 2, 2015. REUTERS/Toby Melville 

Venus Williams of the U.S.A. changes ends during her match against Aleksandra Krunic of Serbia at the Wimbledon Tennis Championships in London, July 3, 2015. REUTERS/Stefan Wermuth

Caroline Wozniacki of Denmark serves during her match against Saisai Zheng of China at the Wimbledon Tennis Championships in London, June 30, 2015. REUTERS/Henry Browne 

Grigor Dimitrov of Bulgaria plays a shot through his legs during his match against Federico Delbonis of Argentina at the Wimbledon Tennis Championships in London, June 29, 2015. REUTERS/Toby Melville

A Ball boy gives Joao Sousa of Portugal his racket back during his match against Stan Wawrinka of Switzerland at the Wimbledon Tennis Championships in London, June 29, 2015. REUTERS/Suzanne Plunkett 

Kei Nishikori of Japan reacts after winning his match against Simone Bolelli of Italy at the Wimbledon Tennis Championships in London, June 29, 2015. REUTERS/Toby Melville TPX IMAGES OF THE DAY 

Victoria Azarenka of Belarus hits a shot during her match against Kirsten Flipkens of Belgium at the Wimbledon Tennis Championships in London, July 1, 2015. REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY

A ball boy holds an umbrella during the match between Andy Murray of Britain and Ivo Karlovic of Croatia at the Wimbledon Tennis Championships in London, July 6, 2015. REUTERS/Toby Melville