New York: Play was suspended due to rain during the third set of the U.S. Open quarter-final between second seed Simona Halep of Romania and former world number one Victoria Azarenka of Belarus on Wednesday.
Azarenka, now ranked 20th after struggling with injuries, was narrowly leading 3-6 6-4 2-1, with Halep serving at 40-15 in the fourth game of the third set when a light rain began falling, causing slick conditions on the hardcourt.
A threatening forecast of stormy weather had earlier caused organisers to move up the scheduled men`s singles quarter-final between second seed Roger Federer and France`s Richard Gasquet by an hour to 7 PM ET/2300 GMT).
The halt at Louis Armstrong Stadium was the first rain delay of the championships at Flushing Meadows, where the framework for a centre court roof is in place and expected to be ready for use at next year`s tournament.
The winner of the match between Azarenka and Halep will next meet 26th-ranked Italian Flavia Pennetta in the semi-finals.
Pennetta earlier beat two-times Wimbledon champion Petra Kvitova in three sets.
The other women`s semi-final on Thursday will pit top-seeded world number one Serena Williams against Italy`s Roberta Vinci.