World number five Samantha Stosur has been shocked in the quarter-finals of the Madrid Open after a straight-sets defeat by world number 105 Lucie Hredecka.
With neither player dropping a service game in a tense opening set, Hredecka snatched three mini-breaks in the tie-break to take it 10-8.
The Czech was again more than a match for the 2011 US Open winner in the second as she forced another tie-break.
Australian Stosur proved tougher to grind down this time, but Hredecka found two mini-breaks to win the set 8-6 and claim the unlikely victory.