Dimitrov roars back to stun Federer, reach US Open semifinals

Grigor Dimitrov picked a great time to get his first win over Roger Federer.

The Bulgarian stunned the five-time US Open champion Tuesday, roaring back after losing the third set to claim an unlikely 3-6, 6-4, 3-6, 6-4, 6-2 victory at Arthur Ashe Stadium.

Dimitrov, ranked No. 78 in the world, went into the contest having lost all seven of his previous encounters with the Swiss legend, including 16 of the last 18 sets between the pair. He kept his nerve this time around, though, putting together a steady performance that was highlighted by some excellent shot-making at key moments.

Federer, on the other hand, was undone by uncharacteristic sloppiness. And, potentially, an ailment.

In a match that lasted over three hours, the 38-year-old seemed to run out of steam, racking up 61 unforced errors.

The No. 3 seed required a rare medical timeout prior to the decisive set after seemingly favoring his back earlier in the match. He returned after a nearly 10-minute break but was never able to recover.

A win would've seen Federer become the oldest Grand Slam semifinalist since Jimmy Connors reached the last four at Flushing Meadows as a 39-year-old in 1991.

Instead, it's Dimitrov who will tangle with Daniil Medvedev on Friday for a place in the US Open final.