Two-time Australian Open champion Azarenka eased past Tatjana Maria 6-2 6-1 in the second round.

The Belarusian former world number one managed to break serve six times in an impressive performance.

Awaiting Azarenka in the last eight is Sofia Kenin, the fifth seed having led Katie Boulter 6-4 4-1 when the Brit retired.

On the other side of the draw, Stephens departed after a surprise 6-3 6-3 loss to qualifier Beatriz Haddad Maia.

Stephens, the 2016 champion, holds a 5-4 win-loss record this year in what has been an indifferent start to her 2019.

Her exit has further opened up the draw, with Haddad Maia to meet Wang Yafan, who led Monica Puig 4-1 when the Puerto Rican retired.

Seeds Donna Vekic and Johanna Konta set up a last-eight clash after straight-sets victories.

Vekic got past qualifier Christina McHale 6-4 7-5, while Konta cruised to a 6-4 6-1 win over Varvara Flink.

The other quarter-final will be between Zheng Saisai and Bianca Andreescu after their wins over Timea Babos and Mihaela Buzarnescu respectively.

At the Oracle Challenger Series at Indian Wells, second seed Alison Riske and sixth seed Sara Sorribes Tormo were among the players reaching the third round.