World number six Juan del Potro crashed out of the Madrid Open on Thursday, after Serbia’s Dusan Lajovic came back from a set down to beat the Argentine.
The Serb won 3-6 6-4 7-6(6) in the third round match.
Del Potro looked in complete control as he converted two break-point opportunities to take the opening set.
But Lajovic, ranked 95 in the world, dug deep to stay in the contest.
A break midway through the second set was enough for Lajovic to force a decider before he wrapped up his first career victory over a top-10 opponent in the tiebreak.
In the quarter-finals, Lajovic will meet South Africa’s Kevin Anderson who overcame German Philipp Kohlschreiber 6-3 7-6(7).
Britain’s Kyle Edmund followed up his surprise win over Novak Djokovic by defeating world number 10 David Goffin.
The victory enabled him to reach the last eight of an ATP Masters 1000 event for the first time in his career.
The 23-year-old broke his Belgian opponent’s serve twice in the opening set and once in the second to seal a 6-3 6-3 victory in an hour and 12 minutes.
“I managed my game very well,” the Briton said. “My game is better the way I manage it and pick the moments not to be aggressive.
He added: “If I don’t pull the trigger too often, then I play well. It’s about being controlled and relaxed and not worrying too much. Goffin is a top player. So, I’m very pleased.
“My new trick is to try and continue that momentum and not just have a good win and not back it up.”
Edmund will next face Canadian youngster, Denis Shapovalov, who achieved a 6-4 6-4 win over compatriot Milos Raonic.