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.
"If I'm going to be supposedly taking too long between points on one or two points, then grunting that loud for that long is like an extended grunt as well. It's making a noise when you're hitting the ball. It's annoying.
"When I have been on the court or off it, it's never been something I have found to be really that off-putting.
"But if it's going to be suggested that I am using gamesmanship by taking too long, then you can't be making noises like that on the court. I haven't experienced it like that before.
"It was extremely, extremely loud, more than what I have experienced from any other player on the tour."