Tommy Haas has suffered a surprise three-set defeat in the first round of the Madrid Open against Dutch qualifier Igor Sijsling.
The German veteran, who was seeded 14th, claimed the opening set 6-3 before Sijsling fought back emphatically to level the match 6-1 in the second.
World number 59 Sijsling then broke Haas three times in the decider to seal the win 6-4.
The 26-year-old Dutchman will face Finland's Jarkko Nieminen for a place in the third round.