Ons Jabeur, 5th in the world and finalist last year, had to fight again on Thursday to snatch 7-6 (9/7), 4-6, 6-3 against the Czech Linda Noskova (41st) her qualification for the third round of the US Open.
The Tunisian, suffering, had already drawn on her reserves on Tuesday to pass the first round 7-5, 7-6 (7/4) against Colombian Camila Osorio.
Jabeur will try on Saturday to climb into the round of 16 by facing another Czech, Marie Bouzkova (31st).