Australian Open and Wimbledon champion Djokovic closes the day programme at Arthur Ashe Stadium against 89th-ranked Joao Souza of Brazil.
Serbia's Novak Djokovic celebrates winning the first set during his men's singles match against Switzerland's Stanislas Wawrinka on day nine at the 2014 Australian Open tennis tournament in Melbourne on January 21, 2014. IMAGE RESTRICTED TO EDITORIAL USE - STRICTLY NO COMMERCIAL USE AFP PHOTO / GREG WOOD
Serena Williams of the US celebrates winning the first set against Russia's Maria Sharapova during their final tennis match as part of the 2012 London Olympic Games at the All England Tennis Club in Wimbledon, southwest London, on August 4, 2012. AFP PHOTO / MARTIN BERNETTI
Tennis ball
1984, Paris, France --- Jimmy Connors waits to return a serve in a tennis match at the 1984 French Open. --- Image by © Gilbert Iundt/TempSport/Corbis
19 Jun 2015, Halle, Rhineland, Germany --- Halle (westfalen), Germany. 19th June 2015 -- Roger Federer (SUI) hits a backhand during the quarterfinal of the 2015 Gerry Weber Open in Halle (Westfalen) against Florian Mayer (GER). -- Swiss tennis player Roger Federer beat German player Florian Mayer in the quarterfinals of the 2015 Gerry Weber Open in Halle (Westfalen), Germany in straight sets 6-0 7-6. --- Image by © Janine Lang/Demotix/Corbis
29 Aug 2015, New York City, New York State, USA --- New York, United States. 29th August 2015 -- Serena Williams speaks with members of the media during the 2015 U.S. Open tournament kids day in New York City, US. -- Top ranking players, including Novak Djokovic, Maria Sharapova, Rafael Nadal and Serena Williams, visit the US open during the kids day in Flushing Meadows the venue for the 2015 U.S. Open tennis tournament. --- Image by © VIEW press/Demotix/Corbis
Spain's Rafael Nadal celebrates after victory in his men's singles semi-final match against Switzerland's Roger Federer on day twelve of the 2014 Australian Open tennis tournament in Melbourne on January 24, 2014. IMAGE RESTRICTED TO EDITORIAL USE - STRICTLY NO COMMERCIAL USE AFP PHOTO / MAL FAIRCLOUGH
04 May 2015, Madrid, Spain --- Feliciano Lopez in their first round match during day third of the ATP Mutua Madrid Open tennis tournament at the Caja Magica on May 3, 2015 in Madrid, Spain (Photo by Oscar Gonzalez/NurPhoto) --- Image by © Oscar Gonzalez/NurPhoto/Corbis
08 May 2014, Madrid, Spain --- Spain, Madrid : Canadian tennis player Milos Raonic returns the ball to Scottish tennis player Andy Murray during the Madrid ATP Masters Series Tournament tennis match, day 8 on May 8, 2015 in Madrid . (Photo by Guillermo Martinez/DPI/NurPhoto) (Photo by Guillermo Martinez/NurPhoto) --- Image by © Guillermo Martinez/NurPhoto/Corbis
26 Oct 2014, Basel, Switzerland --- David Goffin (BEL) during the final of the Swiss Indoors at St. Jakobshalle in Basel, Switzerland on October 26, 2014. (Photo by Miroslav Dakov/NurPhoto) --- Image by © Miroslav Dakov/NurPhoto/Corbis
16 Jan 2015 --- KAROLINA PLISKOVA (CZE) loses in the women's final against Petra Kvitova (CZE) during the APIA International in Sydney, Homebush - 16/01/2015 ph. Andrea Francolini --- Image by © Andrea Francolini/Corbis
27 Jun 2015, Eastbourne, East Sussex, England, UK --- AEGON International 2015- Eastbourne - England - Womens Singles Final. Belinda Bencic of Switzerland in action playing single handed forehand against Agnieszka Radwanska of Poland. Saturday, 27th, June, 2015 - Devonshire Park, Eastbourne, East Sussex, England, United Kingdom (Photo Credit: Nick Walker/Sport Picture Library) --- Image by © Nick Walker/Corbis
25 Jun 2015, Eastbourne, East Sussex, England, UK --- Agnieszka Radwanska - Aegon International 2015 - Eastbourne - England, Agnieszka Radwanska of Poland in action playing single handed forehand against Tsvetana Pironkova of Bulgaria. Thursday, 25, June, 2015 - Devonshire Park, Eastbourne, East Sussex, England, United Kingdom (Photo Credit: Nick Walker/Sport Picture Library) --- Image by © Nick Walker/Corbis
20 Jan 2015, Melbourne, Victoria, Australia --- 20.01.2015 Australian Open Tennis from Melbourne Park. Venus Williams of the USA returns a shot in her match against Maria-Teresa Torro-Flor of Spain on day two of the 2015 Australian Open at Melbourne Park, Melbourne, Australia. --- Image by © Essi Lim/ActionPlus/Corbis