A French government Covid-19 curfew of 9pm means that nine out of the 10 scheduled evening sessions at the tournament have to be played without spectators inside the 15,000-capacity Court Philippe Chatrier.

Djokovic saw off world number 66 Sandgren 6-2, 6-4, 6-2 for his fourth win in four meetings with the American.

Top seed Djokovic, the champion in Paris in 2016, is attempting to become the first man in more than 50 years to win all four Slams multiple times.

He will face Pablo Cuevas of Uruguay for a place in the last 32.