Big-serving Elena Rybakina will aim to retain her title but other players have emerged as serious contenders:
Victoria Azarenka's China Open title defence wilted in the first round when the Belarussian lost to Germany's Andrea Petkovic 6-4, 2-6, 6-4 on Monday.
Garbine Muguruza emerged as a favourite to win the Italian Open after beating Latvia's Jelena Ostapenko to reach the third round after world number one Angeliquer Kerber had earlier bowed out to Estonian qualifier Anett Kontaveit.
Serena was beaten by Jennifer Capriati while Venus lost to Russia's Anastasia Myskina in the women's quarter-finals at the French Open.
The Williams sisters will in the United States' Fed Cup match against Belgium in April.
American Serena Williams won her seventh Wimbledon singles crown, and equalled the professional era record of 22 grand slam titles, with a 7-5, 6-3 victory over Germany's Angelique Kerber on Saturday:
Petra Kvitova, who missed part of the 2017 season after a home invasion left her with a badly cut left hand, continues her remarkable comeback when she faces American Venus Williams.
The Canadian's win sets up a semi-final clash with Del Potro on Saturday that will pit power against power.
Serena Williams plans to play fewer tournaments in the future to aid her quest to win more Grand Slam titles, according to her coach Patrick Mouratoglou.
Serena Williams will try to take a step closer to history on Saturday when she plays her third-round match at the US Open.
Top seed Serena Williams came from a set down to book her place in the Stanford Classic semi-finals with a hard-earned 2-6, 6-3, 7-5 win against fifth-seeded Serb Ana Ivanovic on Friday.
Sania Mirza and Rohan Bopanna sqaundered a set advantage to lose to USA's Venus Williams and Rajiv Ram 6-2, 2-6, 3-10 in the Rio Olympics semi-finals on Saturday.
Osaka had pulled out of the French Open citing mental health and revealed that she suffered long bouts of depression since the US Open in 2018.
Serena Williams marked her first European appearance of the season with victory on the Madrid Open's striking blue clay courts on Monday, but her sister Venus crashed out in the second round.
Defending champion Novak Djokovic was handed a tough opening round at Wimbledon when Friday's draw paired him with Germany's Philipp Kohlschreiber.
Top-seeded Serena Williams said on Friday that she was not sure about the state of her balky right shoulder but felt more relaxed entering next week's US Open than last year.
The victory sent the Swiss through to the Italian Open final against 16th seed Dinara Safina.
India's focus on day eight will be centered around tennis mixed doubles pair of Sania Mirza and Rohan Bopanna who are to take on the US pair of Venus Williams and Rajeev Ram, on Saturday night, in the semi-finals at the Rio Olympics.
With an unrestrained jig at the most hallowed hallway in tennis, Serena Williams confirmed that 'Her Way' was just about the most formidable method the women's game has seen.
Bianca Andreescu rolls to first-round win at Strasbourg.
Ruthless Serena Williams underlined her dominance at the top of women's tennis on Sunday, completing her year in style with a 6-2, 7-6 defeat of big sister Venus in the final of the WTA Championships.
Venus Williams will replace sister Serena, who suffered an ankle innjury, in the Fed Cup tie against Belgium.
The World No 1 becomes earliest qualifier for WTA Finals
A round-up of all tennis action on Saturday.
Former champions Venus and Serena Williams pulled out of the women's doubles at Wimbledon.
Becoming the WTA number one in the world is a dream come true'
Sania Mirza and Bethanie Mattek set up a quarter-final clash with American sisters Venus and Serena Williams after getting past the Uzbek-Belarussian pair of Akgul Amanmuradova and Darya Kustova in the third round of Wimbledon Championships.
Czech duo Andrea Hlavackova and Lucie Hradecka won the U.S. Open women's doubles title on Saturday with a 6-7(4), 6-1, 6-4 win over Australia's Ashleigh Barty and Casey Dellacqua.
Kim Clijsters' brilliant comeback continued at the Cincinnati Open with a 6-4, 4-6, 6-2 win over French Open champion Svetlana Kuznetsova on Thursday, but the Williams sisters both fell at the third round hurdle. Second seed Serena, struggling with a virus, lost 7-5, 6-4 to Austria's Sybille Bammer while in-form Italian Flavia Pennetta ended the hopes of third seed Venus with a 7-6, 6-4 victory.
The tennis obituaries will have to wait for now. The Williams sisters have no intentions of quitting anytime soon.
Factbox on American Serena Williams, who plays sister Venus in the final of the Australian Open on Saturday.
Also in action on the first day at Roland Garros is men's second seed Alexander Zverev who meets Ricardas Berankis of Lithuania on Court Suzanne-Lenglen.
Novak Djokovic will begin his Australian Open title defence against Frenchman Jeremy Chardy, while reigning women's champion Sofia Kenin meets wild card Maddison Inglis, following the draw for the year's first Grand Slam on Friday.
Be it cheering for Roger Federer or Garbine Muguruza at the Wimbledon final, the Hollywood brigade made their presence felt at both, the women's and men's final at Wimbledon over the weekend. We caught a few cine stars watching their tennis heroes in action at the All England Club...
Top seed Agnieszka Radwanska put on a dominant performance against double defending champion Petra Kvitova to ease into the final of the Connecticut Open with a 6-1, 6-1 triumph on Friday.
Twice winner Serena Williams reached the Wimbledon final for the fourth time and third against sister Venus on Thursday with a 6-2, 7-6 victory over Chinese wildcard Zheng Jie on Centre Court.
Williams, who played an exhibition match last December in the United Arab Emirates, where she lost to French Open champion Jelena Ostapenko, said in addition to working on her serve and returns, she needs to manage her time better now that she has her daughter in tow.
US Fed Cup captain Zina Garrison has picked both Williams sisters in her squad to face Russia in next month's semi-final.
