Roger Federer uncharacteristically failed to nail two match points as Dominic Thiem stunned the top seed on the grass in the rain-disrupted Stuttgart semifinals on Saturday.

The Swiss legend, who is returning from a back injury that ruled him out of the French Open, saw his preparations for Wimbledon unravel as Thiem battled through 3-6, 7-6 (9/7), 6-4.

The third seed Thiem, a Roland Garros semifinalist, will play for his fourth title of the season on Sunday against Juan Martin del Potro or Philipp Kohlschreiber.