NEW YORK — Coco Gauff’s first match since enlisting someone to help with her shaky serving got off to a rocky start at the ...

Coco Gauff wishes she weren’t trying out a new service motion in the high stress and high stakes of the U.S. Open.

On the night that she debuted her new service motion, it was Gauff's tennis foundations that propelled her to victory.

But then Gauff learned that MacMillian, a Canadian educated in America and based in South Africa, was available. And then her ...

Yet, she’s still winning nearly 40 percent of the points on her opponent’s serve, including 57 percent of the return points on second serve.

Rule 21 says, “The server shall not serve until the receiver is ready.” The server has to check on the receiver before going into his service motion. It’s a second serve.