Defending champion Simona Halep was knocked out of the French Open 6-2, 6-4 by 17-year-old American Amanda Anisimova in a quarter-final shock.
Form guide for American Serena Williams ahead of Thursday's US Open semi-final clash against Latvia's Anastasija Sevastova:
A rampaging Madison Keys completed an American sweep of the US Open women's quarter-finals on Wednesday, dismissing Estonia's Kaia Kanepi 6-3, 6-3 to guarantee an American champion at the year's final Grand Slam.
Serena Williams overpowered German Carina Witthoeft 6-2, 6-2 to set up a third-round clash with big sister Venus at the US Open on Wednesday.
Fourth seed Angelique Kerber's bid for consecutive Grand Slam titles ended when 29th seed Dominika Cibulkova defeated the German 3-6, 6-3, 6-3 in the US Open third round on Saturday.
A summary of Friday's tennis action from around the world.
Top seeds Novak Djokovic and Serena Williams face challenging early tests at the US Open following Friday's draws for the year's last Grand Slam starting on Monday.
Images from the French Open women's semi-final matches played at Roland Garros on Thursday
Swiss second seed Stan Wawrinka advanced into the semi-finals at the Rogers Cup with a comprehensive 6-1, 6-3 victory over big-serving South African Kevin Anderson at the Aviva Centre in Toronto on Friday.
Top seeded Ash Barty overcame a slow start to defeat Maria Sharapova 6-4 6-1, while Simona Halep battled past Ekaterina Alexandrova 3-6 7-5 6-4 in the second round of the Cincinnati Masters on Wednesday.
Venus Williams staged a spirited comeback to down third seed Petra Kvitova 4-6, 7-5, 6-4 and reach the third round of the BNP Paribas Open in Indian Wells on Saturday.
Images from matches played on Day 4 at the US Open at the Flushing Meadows in New York on Thursday.
ATP says 'no evidence' against Harrison's racist remarks
Spanish fourth seed Garbine Muguruza fine-tuned her preparations for this month's U.S. Open by crushing Simona Halep 6-1, 6-0 in the Cincinnati Open final on Sunday.
IMAGES from matches on Day 10 at the French Open at Roland Garros
Big-serving Canadian Milos Raonic made a strong return to competition on Friday by beating Viktor Troicki 6-3, 7-5 to reach the third round of the Miami Open.
Images from Day 6 of the Australian Open in Melbourne on Saturday.
Images from Day 9 at the French Open.
Images from Day 8 of the Australian Open in Melbourne on Monday.
IMAGES from Day 10 of the US Open matches played in New York on Wednesday
The seventh-seeded Bulgarian advanced to his eighth ATP World Tour Masters 1000 quarter-final with a 6-3, 7-5 victory over Del Potro, who struggled with the intense heat in the closing stages of the one hour, 39 minute match.
PHOTOS from day three of the Wimbledon championships at the All England Lawn Tennis and Croquet Club in London on Wednesday.
Novak Djokovic maintained his unbeaten record against Frenchman Gael Monfils with a 6-3, 6-2 win in the semi-finals of the Rogers Cup in Toronto on Saturday, while Japan's Kei Nishikori also reached the final after beating Swiss second seed Stan Wawrinka.
Venus Williams stands in the way of younger sister Serena's bid for a calendar-year Grand Slam after reaching the quarter-finals with a 6-2, 6-1 rout of Estonian teenager Anett Kontaveit on Sunday.
Top seed Agnieszka Radwanska's title defence at the Sydney International lasted just 92 minutes when she was dumped out of the second round by Bethanie Mattek-Sands on Tuesday.
Images from the matches played on Day eight of the 2018 Australian Open at Melbourne Park on Monday
Karolina Pliskova lost her cool over a line call and bashed a hole into the umpire's chair with her racket after suffering a 3-6, 6-3, 7-5 defeat by Maria Sakkari in the Italian Open second round on Wednesday.
Serena Williams will face Maria Sharapova for the Australian Open title
IMAGES from Day 6 of the Australian Open in Melbourne, on Saturday.
Serena Williams and Marin Cilic both survived third round scares on Friday to keep their US Open title defences on track but there was no escape for Rafael Nadal with the twice-winner going down in a late night thriller.
Maria Sharapova made it a remarkable 20 victories from 23 grand slam quarter-finals but was pushed all the way at Wimbledon on Tuesday by feisty American Coco Vandeweghe before emerging a 6-3, 6-7(3), 6-2 winner.
World number one Simona Halep saved three match-points before edging past an inspired Lauren Davis 4-6, 6-4, 15-13 in a thrilling marathon to reach the fourth round of the Australian Open on Saturday.
Images from matches played on Day 4 of the Australian Open at Melbourne Park on Thursday
Former world number one Andy Murray withdrew from the Brisbane International with a hip problem on Tuesday, further putting in doubt the Briton's prospects of being fit in time for the Australian Open later this month.