Rain wiped out all of the scheduled action here on Tuesday, and only about 15 minutes of tennis was staged on Wednesday because of inclement weather in New York.
A second-seeded Nadal handled fellow left-hander Gilles Muller of Luxembourg 7-6 (7-1), 6-1, 6-2 at Arthur Ashe Stadium. The match was postponed on Tuesday and halted because of rain on Wednesday, with Muller leading 3-0 in the opening set.
Nadal moved on in 2 hours, 8 minutes, as Muller piled up 43 unforced errors and had his big serve broken six times.
The capable Muller stunned Nadal in a second-round affair at Wimbledon back in 2005. Nadal avenged that defeat by besting Muller in the third round at Wimbledon 2011 earlier this summer.
The fourth-seeded Murray, meanwhile, flattened 22-year-old American Donald Young 6-2, 6-3, 6-3. The match was suspended on Wednesday, with Young leading 2-1 in the first set. But the American was no match for the Brit on Day 11.
Murray, who closed out his Thursday exercise with a resounding ace, ultimately dismissed the overmatched Young in just under two hours, as the American littered the court with 53 unforced errors and had his serve broken a whopping eight times.
Young stunned Murray in the second round at an ATP Masters event at Indian Wells back in March.
The three-time Grand Slam runner-up Murray was this year's Aussie Open runner- up to Djokovic and lost to the great Roger Federer in the 2008 U.S. Open finale.