Andy Murray was unhappy with Carlos Berlocq's on-court behaviour after knocking the Argentine out of the BNP Paribas Open in Indian Wells.
The British No 1 battled to a 7-6 6-4 victory in a bad-tempered fourth-round clash in which the players exchanged angry words during the ninth game of the opening set.
Berlocq accused Murray of taking too long between points, and the Scot responded by complaining to the umpire over the volume of his opponent's grunting.
"He complained I was taking too long between the points, and there were maybe one or two points where that could have been an issue," said Murray.
"But when someone is grunting like that it's every single shot. And also, when you're doing it that loud, but you aren't doing that on every single shot, there is obviously a reason for why you're grunting like that.