There is also new access to data, provided this season to the Women’s Tennis Association by the German software company SAP. Many players are not yet heavy users of the fast-growing database, although Sam Stosur and Ana Ivanovic are exceptions, according to Jenni Lewis, head of tennis technology at SAP. But coaches are using it.

“We are getting more statistics about where returns are landing, and we can use those patterns to anticipate better on third balls,” Fissette said. “That will help in the future more and more.”

Open-stance ground strokes are also critical in the server’s race against the clock, making for quicker transitions and a more stable platform. Modern physical training has played a role, too.

“They usually can’t back up; they don’t have the time — they finish the serve and, boom, the ball is at them,” Austin said. “They have to be flexible and have that core strength. It’s all about using your legs and having great timing, because if you don’t, a ball like that is going to end up in the stands. The key is the abbreviated swing. Take a big swing, and you’re done.”

To accelerate the learning curve in training, a hitting partner will sometimes feed a ball to the server in practice from close range almost immediately after a serve, forcing her to hit the next shot even sooner than she would against a big returner. The goal is to train the reflexes and render the third shot more manageable.

But Saviano says that artificial approach has its limits.

“When somebody feeds, it’s certainly not the same as when you are seeing information from the returner and squaring up accordingly,” he said. “Every little nuance in picking up the ball, recovering and making your split step is important.

“Your split step is predicated on when the returner impacts the ball. You should be in the air when they are hitting it, and then you land and you move. All those are integral parts. So how you train that third shot is critical.”