Coco Gauff has used a powerful serve and great court coverage to stand out among the emerging young stars in women’s tennis. Dr. Mark Kovacs, a sports scientist and coach who has worked with Gauff, helps explain the parts of her game that make her so good, as well as aspects she can improve.

Coco Gauff reacting after her second-round victory Thursday over Timea Babos at Louis Armstrong Stadium.
Uli Seit for The New York Times

A Great Serve in the Making

Gauff, at 15, is nearly two years younger than anyone else in the United States Open, yet she already serves harder than many of the women in the tournament, reaching 118 m.p.h. “She has all the makings of having possibly the best serve ever,” Kovacs says.

But Kovacs cautions that Gauff is still a work in progress, with lots of room to grow. Not great news for her competitors.

Below, Kovacs highlights the parts of Gauff’s serve that are similar to other great servers, and the places where she can improve.

Mastering Motion

Gauff’s movement is probably her best asset right now and what gives her the ability to compete with top players. Kovacs says she moves efficiently and reminds him a lot of Sloane Stephens, whom he worked with at a similar age.

Kovacs says the players both cover ground in large steps, whereas most girls at that age cover them in small, less efficient steps. “She takes half a step less than a lot of other girls to cover the same distance.”

This makes her faster and more efficient, and places her in a better position to defend.

Sloane Stephens reaches to return a shot from Anna Kalinskaya during the first round of the U.S. Open.
Adam Hunger/Associated Press

In her first-round match against Anastasia Potapova on Tuesday, Gauff repeatedly displayed her trademark speed and footwork, crisscrossing the court to run down balls. It was never more evident than during the final point of the match, shown below.