15-year-old rising tennis star Coco Gauff might have to put her dad in a time-out -- he accidentally cursed while coaching her during a match ... and she called him out for it!!
The whole interaction was thankfully caught on camera because Coco and her dad/coach were mic'd up for her ASB Classic match in New Zealand ... and in between sets, he gave her a pep talk.
Her dad, Corey, is heard giving out compliments left and right ... but got a bit carried away when he said, "There's one thing you did the last 3 games, you ain't give up no free points on no damn serve.