Frances Tiafoe (above) was about to serve to Mitchell Krueger during the men's singles match in Florida when the noise was heard. Initially the commentator Mike Cation thought the sound was coming from a prankster in the stands with a loudspeaker, until it became clear that the moans of pleasure were coming from a nearby apartment complex.
Tiafoe couldn't help but flash a smile at the camera when the sounds were heard, and the crowd began to giggle.
The players had a good sense of humour about it - with Krueger hitting a ball in the direction of the building as Tiafoe yelled 'It can’t be that good!'
Cation gave the, likely dehydrated, couple a hat tip on his Twitter after the match.