Venus Williams beat Elise Mertens in a marathon three-set match in Rome despite missing out on eight match points.
Kiki Bertens beat Sloane Stephens in straight sets at the Madrid Open to book her place in her third WTA Premier 5 final.
Naomi Osaka survived a testing three-set encounter with Sara Sorribes Tormo to progress to the third round in Madrid for the first time.
Naomi Osaka battled back from a seemingly impossible position in the decider to edge out Donna Vekic and reach the semi-finals in Stuttgart.
Naomi Osaka maintained her grip on the World No.1 ranking with a serene straight-sets victory over Su-Wei Hsieh in Stuttgart.
Anett Kontaveit started her clay court campaign in style with a straight-sets win over Caroline Garcia at the Porsche Tennis Grand Prix.
Madison Keys played superbly to beat Puig in straight sets, while Wozniacki beat her good friend Martic for the sixth consecutive time.
Madison Keys progressed to the quarter-final stage of the Volvo Car Open for the fourth time in her career with an impressive straight-sets win over Jelena...
2018 Champion Kiki Bertens crashed out of the Volvo Car Open in the third round with a straight-sets loss to Maria Sakkari.
Ashleigh Barty beat Karolina Pliskova in straight sets in the Miami Open final to win her first Premier Mandatory title.
Simona Halep won two tight sets against Wang Qiang to earn a 6-4 7-5 victory and set up a semi-final meeting with Pliskova or Vondrousova.
Simona Halep and Petra Kvitova breezed to comfortable straight-sets wins to increase the likelihood that they will face each other in the final.
Daria Kasatkina lost her seventh match of the year to Venus Williams, while Mertens, Sevastova and Collins were also knocked out.
Serena Williams and Angelique Kerber both survived testing three-set contests on their way into the third round of the Miami Open.
Petra Kvitova got her Miami Open campaign off to a flyer with a straight-sets win over Maria Sakkari.
Belinda Bencic came up with some breathtaking tennis to knock out defending champion Naomi Osaka in Indian Wells.
Belinda Bencic produced some great tennis to beat Aryna Sabalenka in three sets and earn a quarter-final meeting with Simona Halep in Dubai.
Naomi Osaka progressed to the Australian Open semi-final and moved ahead in the race for World No.1 with a dominant win over Svitolina.
Elina Svitolina advanced to the Australian Open quarter-finals for the second year in a row with victory over Madison Keys.
Ashleigh Barty beat Maria Sharapova in an exciting three-set match to progress to her first Grand Slam quarter-final.