The 23-year-old Lavtian fired 27 winners in the 6-4, 6-2 sweep over one of the favourites for the women’s singles crown.
"I tried to be aggressive but not miss too much as she's such a great player," said Ostapenko who had lost in the first round in both of her visits to the tournament since her 2017 triumph.
"I had to bring the best tennis that I could,” added the world number 43.
Former champion @JelenaOstapenk8 moves into round three with a ruthless dismissal of the No.2 seed 👇#RolandGarros
— Roland-Garros (@rolandgarros) October 1, 2020
The defeat completed a miserable year at the Grand Slam tournaments for Pliskova.
The 28-year-old Czech only made the third round at the Australian Open and second round at the US Open.
Pliskova’s compatriot, Petra Kvitova, fared better. The seventh seed was businesslike in her straight sets win over the world number 94 Jasmine Paolini. Kvitova dispatched the Italian 6-3, 6-3 in 84 minutes.
