Sam Stosur progresses at Miami Open March 21, 2019 by AAP

SYDNEY, AAP - Australian tennis star Samantha Stosur has progressed to the second round of the Miami Open after a first-up win over Russian Evgeniya Rodina.

Stosur triumphed 6-4 6-2 over Rodina in just over 90 minutes, hitting five aces and winning three quarters of all breakpoints.

The world No.78 will face American Madison Keys in the second round, with the victor likely to face Australian Ashleigh Barty.

She said it'd be a major challenge, having not played Keys since 2013, when she beat the world No.16 at Indian Wells and Osaka.

"We've both got a bit more experience than back then, she was pretty young when I played her last time," the 34-year-old Stosur told reporters.

"She has a big game, big serve, big forehand."

Australian Ajla Tomljanovic's match against Anna-Lena Friedsam was rained out after German won the first set 6-4. The match will continue on Thursday, while Daria Gavrilova's match against Slovakian Viktoria Kuzmova will begin.

Elsewhere, Belarusian Victoria Azarenka ousted Slovakian Dominika Cibulkova in three sets, while top-seeded stars Naomi Osaka, Simona Halep, Petra Kvitova and Sloane Stephens are yet to hit the court.