The 19-year-old Briton won the first set 6-3 in fine style but her game fell away dramatically as her opponent, who is banned from playing at Wimbledon following the All England Lawn Tennis Club's ruling over Russian and Belarussian players, took the next two sets 6-1, 6-1.

Raducanu, seeded 12^th in her French Open debut, was unable to take any of five break points in the third game of the deciding set.

Sasnovich held serve after a 13-minute game, broke in the next and then moved towards victory.

Sasnovich is allowed to play as a "neutral" player at the French Open, without a national flag or symbols, as is the case on the Women's Tennis Association Tour.  

Raducanu has thus lost in the second round in her two Grand Slams since the win in New York last year.

Sakkari’s 6-7, 6-7 defeat by the Czech Republic’s Karolína Muchová means that four of the top six seeds have failed to reach the third round.

Sasnovich’s compatriot Victoria Azarenka, seeded 15, progressed with a 6-1, 7-6 win over Germany’s Andrea Petkovic.

Three-time Grand Slam winner Angelique Kerber, seeded 21 and another German, defeated France’s Elsa Jacquemot 6-1, 7-6.

Sloane Stephens of the United States, unseeded, earned a 3-6, 6-2, 6-0 win over Romania’s 26^th seed Sorana Cîrstea.

Stephens was a finalist at Roland Garros in 2018.

Stephens’ US compatriot, 18-year-old Coco Gauff, seeded 18^th, progressed at the expense of Alison Van Uytvanck of Belgium, 6-1, 7-6.

Canadian teenager Leylah Fernandez, the US Open runner-up last year, beat reigning French Open and Olympic women's doubles champion Kateřina Siniaková of the Czech Republic 6-3, 6-2.