Indian Wells, California - Brazilian Thomaz Bellucci was gifted a walkover into the fourth round of the Indian Wells ATP tournament on Tuesday when Russian Nikolay Davydenko withdrew from their match due to illness.
It was not certain whether Davydenko had succumbed to the viral infection which has already forced eight players to pull out of Indian Wells, tournament officials said.
Bellucci will next play either three-times champion Roger Federer or Canadian Milos Raonic who were scheduled to play in Tuesday's evening session.
In other third-round matches, twice winner and second seed Rafael Nadal was set to face fellow Spaniard Marcel Granollers while Argentina's Juan Martin del Potro was playing Spaniard Fernando Verdasco in the opening encounter of the day.
Wimbledon champion Petra Kvitova is among the players who have already pulled out of the tournament because of the virus, which local health authorities have described as a 48-hour bug transmitted by air and direct contact and not via food.
Early results from the seventh day of the ATP/WTA tournament on Tuesday (x denotes seeding):
Juan Martin de Potro (ARG x9) bt Fernando Verdasco (ESP x19) 6-2, 7-6 (8/6)
Thomaz Bellucci (BRA) bt Nikolay Davydenko (RUS) walkover
Agnieszka Radwanska (POL x5) bt Jamie Hampton (USA) 6-3, 4-6, 3-0 retired