NEW YORK — They are two different players and, at times, it looks as if they’re playing two different games.

There’s the Serena Williams style, filled with intimidation and huge shots. And there’s the way Caroline Wozniacki does it, with great hustle and even better conditioning.

Both players made it through the fourth round of the U.S. Open on Monday and stayed on a path that could collide in the semifinals — Williams with a big-serving 6-3, 6-4 victory over No. 16 Ana Ivanovic and Wozniacki with a 6-7 (6), 7-5, 6-1 win over No. 15 Svetlana Kuznetsova that took 3 hours, 2 minutes.

The 28th-seeded Williams is the only one of the eight women left in the draw who has won a Grand Slam title, which could answer the question of whose style works better in the sport’s biggest events.

But Wozniacki is top-seeded at the U.S. Open and No. 1 in the rankings — tops in a system that rewards consistency more than big moments. By that standard, it is, indeed, hard to find anyone better.

“I know I can be out there for hours and hours,” she said. “It’s great to know that, and it’s great to know that it doesn’t matter how long the match takes. I mean, I will not lose because I’m not physically well.”