The Paris rain washed away two of the leading contenders at the French Open.
Second seed Agnieszka Radwanska and 2014 finalist Simona Halep were both in control when their matches were suspended on Sunday evening.
But, when play was finally able to resume on Tuesday afternoon, the tables were turned in damp, heavy conditions and it was Tsvetana Pironkova and Sam Stosur who moved through to the quarter-finals.
Radwanska must have thought she was nearly there on Sunday when she left the court leading world number 102 Pironkova 6-2 3-0.
But the Pole relies on touch rather than power and could not exert any control.
Pironkova, renowned as a dangerous player on grass and other fast surfaces, won the first 10 games either side of another lengthy rain delay and eventually ran out a 2-6 6-3 6-3 winner.
The Bulgarian, who had never previously been beyond the third round at Roland Garros, joins American Shelby Rogers to make it two players ranked outside the top 100 in the last eight.
Things were tighter between Halep and 2010 finalist Stosur on Sunday, with the Romanian leading 5-3, but the conditions clearly favoured the more powerful Stosur and she dominated to win 7-6 (7/0) 6-3.
The Australian, who now plays Pironkova, last reached the quarter-finals at Roland Garros in 2012.