World number two Daniil Medvedev has withdrawn from the Monte Carlo Masters after testing positive for coronavirus.
Second seed Medvedev had a first-round bye for the clay-court tournament, which began on Monday.
"My focus now is on recovery and I look forward to getting back out on tour as soon and as safely as possible," the 25-year-old said.
Medvedev practised with world number three and 11-time Monte Carlo champion Rafael Nadal on Monday.
The Monte Carlo Masters takes place from 12-18 April.