Cincinnati, OH, USA, 19 August 2015 | AFP

Rising star Daria Gavrilova has caused a major upset at the Cincinnati Masters, beating tournament No.16 seed Sara Errani in the opening round on Tuesday.

The Russian-born Gavrilova, who now lives in Melbourne, beat the Italian 6-1 4-6 6-2.

Last week, Errani went all the way to the semifinals at Toronto’s Rogers Cup, beating Victoria Azarenka along the way.

Yet the 21-year-old Gavrilova, ranked 36th, sent down five aces in an impressive performance to set up a second-round match with Karin Knapp, also of Italy.

Cassey Dellacqua, however, is out of the tournament but not before putting up a brave fight against German Mona Barthel.

The world No.60 was beaten 2-6 6-3 7-6(4) in just over two hours by her fellow qualifier, who is ranked two spots below her.

Dellacqua next heads to the WTA Connecticut Open in New Haven for a final week of preparation ahead of the US Open.