NEW YORK (AP) — The Latest on the U.S. Open tennis tournament (all times local):
Madison Keys returned to the U.S. Open quarterfinals with a 6-1, 6-3 victory over No. 35 seed Dominika Cibulkova of Slovakia.
Keys was an Open finalist a year ago and lost to Sloane Stephens. She lost to Stephens again this year in the French Open semis.
The 14th-seeded Keys will play the winner of the Carla Suarez Navarro vs. Maria Sharapova match in the night session at Arthur Ashe Stadium.
Keys has reached at least the quarterfinals in three of the four Grand Slams this year. She had six aces and no double faults Monday in perhaps her best performance of the tournament.
The extreme heat policy is back in effect at the U.S. Open.
A 10-minute break will be allowed between the second and third sets of women's singles matches if either player requests one. For men's singles matches, the break would come between the third and fourth sets.
The policy is a rule on the women's tour but not the men's. U.S. Open officials began putting it in play last week, when temperatures first soared into the mid-90s. The policy was in place Tuesday through Thursday.
It was 87 degrees just before the start of Monday's day session on Arthur Ashe Stadium.
The U.S. Open is getting closer to a Roger Federer-Novak Djokovic quarterfinal showdown.
Both play unseeded opponents in the round of 16 Monday at Arthur Ashe Stadium. Federer is a five-time U.S. Open champion and Djokovic has won the tournament twice. Djokovic is 27-0 in the U.S. Open against players ranked outside the top 50.
Federer, the No. 2 seed, faces 55th-ranked John Millman. Djokovic, the No. 6 seed, takes on 68th-ranked Joao Sousa. Neither Millman nor Sousa has reached the final eight at a Grand Slam tournament.
There are two other big matches at Ashe when 2006 champion Maria Sharapova plays No. 30 Carla Suarez Navarro, and 2017 runner-up Madison Keys takes on No. 29 Dominika Cibulkova.
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