NEW YORK — Simona Halep appreciated the help from the heavens in her U.S. Open quarterfinal.

Worn down after dropping the second set to Victoria Azarenka, the second-seeded Romanian got to rest up for nearly an hour-and-a-half when the sky opened up.

“Thanks, God, for raining,” she said in an on-court interview after her 6-3, 4-6, 6-4 victory Wednesday.

Halep, who’s just 5-foot-6, came back on court with a 106 mph ace to prove just how fresh she felt. She advanced to face 26th-seeded Flavia Pennetta, who beat two-time Wimbledon champion Petra Kvitova in another three-set match earlier Wednesday.

Azarenka also is a two-time major champ — as well as a two-time U.S. Open runner-up. Her big-match experience showed for much of the afternoon against Halep, who was seeking to reach just her third major semifinal and first at Flushing Meadows.

The 23-year-old Romanian had 40 winners to 19 unforced errors, while Azarenka had 38 winners to 42 unforced errors. At key moments, though, Azarenka was better, converting all five of her break-point chances while Halep was 6 for 19.

But when that final break point came at 3-3 in the third set, Halep converted it, and that was enough to squeeze out the victory with Romanian gymnastics gold medalist Nadia Comaneci cheering her on.