By Chris Oddo | Friday, August 15, 2014

Serena Williams stayed undefeated against the WTA’s top ten in 2014, downing Jelena Jankovic in straight sets on Friday at the Western and Southern Open, 6-1, 6-3.

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Williams has now won 17 straight against the WTA’s top ten, dating back to last year’s Cincinnati final when the American was upended by Victoria Azarenka in a third-set tiebreaker.

The world No. 1 was never really challenged by Jankovic, who at one point in her career owned a 4-4 record against the 17-time Grand Slam champion. Williams won a quick opener in 25 minutes in which she did not drop a first-serve point or face a break point.

After falling behind a break at 2-1 in the second set, Williams turned it up to win five of the last six games and close out her sixth consecutive victory over Jankovic in 58 minutes.

The world No. 1 will continue her bid for her first Cincinnati title when she faces her good friend Caroline Wozniacki in Saturday’s semifinal round.

Wozniacki eased past Agnieszka Radwanska 6-4, 7-6(5), to snap a personal three-match losing streak against last week’s Rogers Cup champion.

Wozniacki was the steadier player throughout, and she goaded the crafty Radwanska into going for too much in the same way as she did in her heyday as a world No. 1.

Wozniacki improves her post Roland Garros record to 17-3, and reaches her first Cincinnati semifinal with the victory.

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Williams owns a 7-1 lifetime record against Wozniacki, which includes the 4-6, 7-5, 7-5 defeat the Dane suffered in last week’s Rogers Cup quarterfinals.

Williams is seeking the Cincinnati title in her sixth appearance at the event. The only other event that she has played six times without a title is Sydney.

Correction: A previous version of this article stated that Williams' winning streak against the top ten was 16. It is 17.