Djokovic rolls on while Federer, Serena breeze at US Open

Top-ranked defending champion Novak Djokovic rolled into the US Open fourth round 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 on Friday.

"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 favour 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."
"He's a three-time Grand Slam champion, someone that possesses a game with a lot of power, a lot of quality. Let the better player win."
"I actually can go through three sets in a row playing really good tennis."
- De Minaur causes upset -
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"Physically it was quite a tough battle," Pliskova said. "So pleased to be through."
"I need to make sure I serve well and bring variety in as much as I can."