Novak Dkojovic and Serena Williams reached the semifinals in Cincinnati, taking different ways to get there.

The top-ranked players at the Western & Southern Open played early Friday. Dkojovic beat fifth-seeded Stan Wawrinka 6-4, 6-1. Williams followed on center court, struggled with her serve, and rallied to beat Ana Ivanovic 3-6, 6-4, 6-2.

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 last year by beating Ivanovic in the finals. She's using the tournament as a final tuneup for the U.S. Open, where she'll try to complete a Grand Slam sweep.

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