“When you had serve-and-volleyers going against baseliners, that was more of a complete and obvious contrast,” said Tracy Austin, the precocious champion who faced Navratilova frequently. “But in this day and age where the game has become homogenized, we’re looking for any contrast. It’s not as extreme as it used to be, but that’s why Hsieh Su-wei is fun to watch, because you feel like you can see the wheels turning in her mind as to where to place the ball, the geometry of the court. So many players use left and right, and she uses north and south as well.”

Hsieh is constantly changing depth: shifting her target from the backcourt to the forecourt as she mixes in drop shots, angled volleys and sliced and flat groundstrokes.

“Her hands can redirect a shot in either direction on both wings with pinpoint accuracy,” McNamee said. “That’s not normal.”

But outlier fast-twitch defensive skills are required to thrive in an era of abundant power and athleticism, of taller, stronger opposition with superior leverage like Petra Kvitova, Garbine Muguruza, Karolina Pliskova, Madison Keys and the ascendant Aryna Sabalenka.

“I try to do something else than the normal,” said Sevastova, a U.S. Open semifinalist last year whose trademark is the drop shot. “I think it’s important, and it’s my style. It’s not like I don’t have power. I just don’t have that much. But I can handle their pace and hit the ball quickly, and I like variety.”

Dehaes sees more women being able to survive the onslaught.

“I think that has always been the case, but in the last few years we saw it a bit less,” he said. “I think the equipment played a big role, and there was the evolution of women’s tennis with players becoming stronger physically and better technically. Because everyone trains a lot and everyone trains well, which was not always the case in former times. So with more athletic players and more high-performance equipment, the pace of the game accelerated. But I think now the girls are getting used to it and are more able to counter the games of these super-powerful players.”