Federer’s 18-match Grand Slam winning streak ended with a 7-5, 3-6, 7-6 (8), 6-4 quarterfinal loss to Juan Martin del Potro.
The result prevented Federer and Nadal from meeting in the semifinals, which would have been their first head-to-head showdown at Flushing Meadows. It’s the only major tournament where the longtime rivals have never faced each other.
Instead, it will be 2009 champion del Potro against two-time winner Nadal in Friday’s semifinals. The other semifinal is Pablo Carreno Busta against Kevin Anderson.