C oco Gauff says she "did not want to waste time" continuing with something that evidently wasn't working anymore and that's why she decided to abruptly fire coach Matt Daly and add biomechanics expert Gavin MacMillan to her team.

Coco Gauff was as aware as anyone, of course, that her tour-worst double-fault total is a significant problem, so she fired one of her coaches on the eve of the U.S. Open and brought aboard the serve doctor who helped No.

American tennis player Coco Gauff has parted ways with one of her coaches Matt Daly and brought on biomechanics expert Gavin MacMillan.