Mladenovic prevailed in Russia in 2017 but fell at the first hurdle this time around in a frenetic contest that saw each player on the end of a bagel.

The Frenchwoman failed to live with the destructive hitting of Ostapenko, champion at Roland Garros in 2017, as she lost the first set 6-1, only to respond in stunning fashion in the second, which she won without dropping a game.

Ostapenko, knocked out in the first round of the Australian Open replied in kind, though, setting up a second-round clash with Anastasia Pavlyuchenkova - who overcame Alize Cornet - despite hitting 35 unforced errors to her 25 winners.

Victoria Azarenka, whose first-round exit at the Australian Open reduced her to tears as she bemoaned her loss of form, was able to produce a strong performance in a 6-4 6-1 defeat of Margarita Gasparyan, which sealed a second-round meeting with the runner-up in Melbourne, top seed Petra Kvitova.

Julia Goerges, Donna Vekic, Ysaline Bonaventure, Tereza Martincova and Veronika Kudermetova were also victorious in St Petersburg on Monday.

Meanwhile in Hua Hin, Muguruza dispensed of former Wimbledon finalist Sabine Lisicki 6-3 6-4 in 79 minutes, the two-time grand slam champion taking advantage of 26 unforced errors from the racket of the German to progress.

"It was a very tough first round," Muguruza said during her on-court post-match interview. "[Lisicki is] a grand slam finalist and she has a very powerful game, the fastest serves. So I'm very happy with this match."

Jennifer Brady stunned a player ranked 98 places above her by seeing off second seed Caroline Garcia 6-4 7-6 (7-3) and there were also wins for Zheng Saisai, Duan Ying-ying, Tamara Zidansek, Viktorija Golubic, Zhang Shuai and Wang Yafan.