MASON, Ohio (AP) — Novak Djokovic played his best match. Serena Williams? Well, she needed to pull a Serena to move on.

Taking two different approaches, the top seeds at Cincinnati reached the semifinals on Friday, moving step closer to a title that’s been tough for either of them to win.

Djokovic beat fifth-seeded Stan Wawrinka 6-4, 6-1, knocking off the player who beat him for the French Open title. Williams followed on center court, struggled with her serve, and had to “pull a Serena” and rally from behind to beat Ana Ivanovic 3-6, 6-4, 6-2.

“It’s like when you’re down and maybe down a break in a set and a set, and you pull a Serena is when you come back and win,” she said.

Third-seeded Andy Murray reached the semifinals by beating Richard Gasquet 4-6, 6-1, 6-4, his second straight three-set match.

Djokovic has never won at Cincinnati, the only one of the nine ATP Masters events that has eluded him. He’s trying to become the first to win all nine.

Williams won the tournament for the first time on her sixth try last year, beating Ivanovic in the final. She lost in the semifinals at Toronto last week and is using her week in Cincinnati as a final tuneup for the U.S. Open, where she’ll try to complete a rare Grand Slam sweep.