Defending champion Rafael Nadal faced an anxious night after rain intervened with him trailing Argentina's Diego Schwartzman in his French Open quarter-final on Wednesday.
Nadal then fought back to lead the second set 5-3, before heavy rain brought a halt to the last-eight encounter on Court Philippe Chatrier.
Nadal, meanwhile, gave substance to the speculation when Schwartzman, the robust Argentinian world No 11, rocked him out of his comfort zone to break his run of 37 unbeaten sets.
Dominic Thiem and Marco Cecchinato have both completed their quarter-final duties on Tuesday and we cannot say the same for four players who have stepped in to highlight the Wednesday's action, as both quarter-finals are delayed for Thursday due to rain.
At one point Nadal, the reigning champion and 10 times victor, found himself a set and a break down to the diminutive Argentinian Schwartzman.
A rain delay before the 11th seed could cement the break would turn the set on its head - and after a half-hour break, Nadal won three games in a row, only interrupted when the poor weather returned with the top seed two points from levelling the match.
During the ensuing changeover, the left-handed Nadal was treated by a trainer, who applied white tape to both of the No 1-ranked Spaniard's wrists. He hit straight back on two occasions but Schwartzman held to take it 6-3.
The 32-year-old, who was serving for the set, will resume at 30-15 on Thursday.
The victor of the match will play either third seed Marin Cilic or Schwartzman's compatriot Juan Martin del Potro.
Speaking on Eurosport's coverage of the Roland Garros, analyst Annabel Croft said Nadal had to overcome major stress to recover from being a set and break down.