Caroline Wozniacki retired from her third-round Rome Open match with Anabel Medina on Wednesday.
It was the Spaniard who started the match the better, breaking Wozniacki twice to move into a 4-0 lead.
The Dane did break back late in the set, but it was too little too late as Medina secured the opening set 6-4.
Medina won all four games in the second set before Wozniacki, who was clearly struggling, retired with what appeared to be a respiratory illness.