Roger Federer resumes his bid for his first U.S. Open title in 11 years with a quarterfinal under the lights at night against unseeded Grigor Dimitrov.

The 38-year-old Federer is trying to become the oldest male Grand Slam semifinalist since Jimmy Connors was 39 during his 1991 run at the U.S. Open.

Federer's potential path to the final no longer includes nemesis Novak Djokovic — or anyone else who ever has beaten him on a hard court, for that matter.

That's because Federer is a combined 26-0 on that surface against the players left on his half of the bracket. He is 6-0 on hard courts against Dimitrov, 17-0 against Stan Wawrinka and 3-0 against Daniil Medvedev.

Wawrinka, the 2016 champion in New York, takes on the fifth-seeded Medvedev in the afternoon Tuesday.

Serena Williams will test her right ankle after rolling it and tries to return to the semifinals when she plays Wang Qiang. Elina Svitolina meets Johanna Konta in another women's quarterfinal.