She upset Saori Obata of Japan in the first round of the main draw at the US Open.
Both are in superb form and have yet to drop a set at this year's championship. Britain's Murray, the number one seed, will face 28th ranked Fabio Fognini from Italy while Spaniard Nadal will go up against Russian Karen Khachanov, ranked 30.
British World No. 3 Andy Murray cruised to a straightforward victory over Bernard Tomic at the Sony Open but the Williams sisters had contrasting fortunes in Miami on Saturday.
Serena Williams let victory slip from her grasp but gained plenty in defeat at the Eastbourne grasscourt tournament on Wednesday while sister Venus continued her winning return after a five-month injury layoff.
Defending champion Serena Williams has been seeded eighth for next week's Wimbledon championships but sister Venus is lurking down at 24th after the All England Club's seedings committee met on Wednesday.
The world number two secured her first title in Belgium by defeating Italy's Silvia Farina Elia 6-3 6-0 to win the Antwerp Diamond Games.
Venus and Serena Williams stormed into the semi-final s of the women's doubles at Wimbledon, beating Sania Mirza and Bethanie Mattek 6-4, 6-3 in the quarter-finals.
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.
Bianca Andreescu rolls to first-round win at Strasbourg.
Serena Williams and her sister Venus are in preliminary talks to become part-owners of the NFL's Miami Dolphins, the 11-time grand slam winner confirmed on Wednesday.
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.
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:
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.
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.
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.
The Canadian's win sets up a semi-final clash with Del Potro on Saturday that will pit power against power.
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.
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.
Serena Williams will try to take a step closer to history on Saturday when she plays her third-round match at the US Open.
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.
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.
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.
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.
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.
Defending champion Novak Djokovic was handed a tough opening round at Wimbledon when Friday's draw paired him with Germany's Philipp Kohlschreiber.
Three-times winner Serena Williams moved into the Toronto Open second round after beating Spain's Nuria Parrizas Diaz on Monday
The World No 1 becomes earliest qualifier for WTA Finals
The victory sent the Swiss through to the Italian Open final against 16th seed Dinara Safina.
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.
Becoming the WTA number one in the world is a dream come true'
Venus Williams will replace sister Serena, who suffered an ankle innjury, in the Fed Cup tie against Belgium.
Former champions Venus and Serena Williams pulled out of the women's doubles at Wimbledon.
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.
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.
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.