Simona Halep kept telling everybody who would listen: She was a different player. She was stronger mentally. She wanted so much to finally win a Grand Slam title and was sure that, one day, she would.

An already upside-down French Open took another tumble early Sunday. The Nos. 1 and 5 women’s seeds were upset by unseeded players within a half-hour of each other to start the fourth round. Simona ...