NEW YORK:Top-ranked defending champion Novak Djokovic rolled into the US Open fourth round on Friday while Serena Williams and Roger Federer cruised into the last-16 and Kei Nishikori was eliminated.

Djokovic, champion in four of the past five Slams and 16 overall, was less bothered by left shoulder pain that nagged him in the second round in defeating 111th-ranked American Denis Kudla 6-3, 6-4, 6-2.

"That I managed to play almost pain-free, that's a big improvement from last match obviously," Djokovic said. "I didn't know how my body would react. That was nice."

Djokovic, who needed treatment throughout his second-round triumph, skipped practice Thursday in favor of shoulder treatment.

"I'm not going to go into the medical details," he said. "But it definitely was bothering me in the past couple weeks."

The 32-year-old Serbian, a three-time US Open winner, booked a Sunday showdown with three-time Slam winner Stan Wawrinka, the Swiss 23rd seed who eliminated Italian lucky loser Paolo Lorenzi 6-4, 7-6 (11/9), 7-6 (7/4).

"There's something with him that when I get into my best game, I know that it's going to have some big rallies and I'm going to play good tennis," Wawrinka said.

Djokovic, no worse than a US Open semi-finalist since a third-round exit in 2006, leads Wawrinka 19-5 in their all-time rivalry, but they haven't met since Wawrinka beat Djokovic in the 2016 US Open final.

"We've had some great battles over the years, but especially here," Djokovic said. "Let the better player win."

Federer routed Britain's 58th-ranked Dan Evans 6-2, 6-2, 6-1 in only 80 minutes, blasting 48 winners to just seven for Evans. After dropping the first set in his first two matches, the 20-time Grand Slam champion was solid from start to finish.

"What matters the most is that I'm in the third round after those two sort of slow starts," Federer said. "I actually can go through three sets in a row playing really good tennis."

Evans blasted organizers for giving him short rest after a rain-delayed match while his 38-year-old Swiss rival rested after playing Wednesday under the roof at Arthur Ashe Stadium.

Williams continued her quest for a 24th career Grand Slam title to equal Margaret Court's all-time record by crushing 44th-ranked Czech Karolina Muchova 6-3, 6-2 in 74 minutes.

"I had a lot of intensity today, which is really good for me," said Williams, whose next opponent is Croatian 22nd seed Petra Martic.

The 37-year-old American, a six-time US Open champion, last won a Slam at the 2017 Australian Open and hasn't won the US Open since 2014.