Djokovic showed little sign of a shoulder injury as he outclassed American Denis Kudla 6-3, 6-4, 6-2 in New York.

The 32-year-old, seeking a fourth US Open title, will take on Switzerland's Stanislas Wawrinka in round four.

Swiss star Roger Federer set up a meeting with 15th seed David Goffin after sweeping aside Britain's Dan Evans 6-2, 6-2, 6-1.

Federer reacted angrily to questions about the scheduling advantage he had over the Briton, who did not leave Flushing Meadows until about 6pm local time yesterday, before facing the 20-time grand slam champion at noon.

"I don't remember that I asked for something," Federer said.

"I know there was a question about having a preference. 

"But that doesn't mean 'Roger asks, Roger gets'.

"I have heard this too often now. 

"I'm sick and tired of it, that apparently I call the shots.

"The tournament and the TV stations do."

Russian fifth seed Daniil Medvedev joined Federer and Djokovic in the fourth round, following a 7-6, 4-6, 7-6, 6-4 victory over Spain's Feliciano López.

Medvedev was loudly booed by the fans on Louis Armstrong Stadium following an unsportsmanlike conduct code violation in the first set, before he later made an offensive gesture towards the crowd.

"I want all of you to know, when you sleep tonight, I won because of you," the Russian said.

"The energy you gave. 

"The more you do this, the more I win."

In the women's singles, Williams enjoyed a straightforward 6-3, 6-2 win in her clash with Czech Republic's Karolína Muchová.

The American will take on Croatian Petra Martić in the last 16.

French Open champion Ashleigh Barty of Australia beat Greek 30th seed Maria Sakkari 7-5, 6-3, while Karolína Plíšková of the Czech Republic recovered from a mid-game dip in form to overcome Tunisia's Ons Jabeur 6-1, 4-6, 6-4.