Angelique Kerber suffered a shock first-round defeat on the opening day of the French Open.
The number-five seed went down to 18-year-old Anastasia Potapova in straight sets, 6-4, 6-2.
Kerber, the reigning Wimbledon champion, was aiming to complete her career slam at Roland Garros.
2016 winner Garbine Muguruza came from a set down to beat Taylor Townsend 5-7 6-2 6-2, while in the men's draw Stefanos Tsitsipas and Marin Cilic both progressed to the second round with straight sets wins over Maximilian Marterer and Thomas Fabbiano respectively.
Sabalenka, Djokovic headline US Open mixed doubles field
Infantino accuses World Cup critics of spreading hate in open letter
All-rounder Greaves sets test record with five wicket maidens in a row
Pogacar wins record-equalling fifth Tour de France title
