Raducanu out of French Open after second-round loss
The French Open is the last of the Grand Slams that Raducanu has made her debut at and, for a set, it looked as if she was in full control of the contest.
Raducanu was swinging freely through the ball and moving well on a surface she believes could be one of her best in the future.
In the second and third sets, Sasnovich increased her own level significantly, though, while errors became part of Raducanu's work.
Sasnovich will now face Angelique Kerber in the third round at Roland Garros and Raducanu's focus will turn to the forthcoming grass-court season.
Raducanu and Sasnovich, the world No 47 from Belarus, had met only once before on the WTA Tour. The match in Indian Wells last year saw Sasnovich triumph convincingly 6-2 6-4.
It looked to be a different story early on in Paris, though, with Raducanu breaking her opponent in the fifth game of the opening set and looking the more comfortable of the two.
Raducanu used her trusted backhand to stretch Sasnovich across the court and then secured the break with a stunning forehand winner.