Updated

Mason, OH (SportsNetwork.com) - Reigning U.S. Open champion Serena Williams was an easy quarterfinal winner Friday at the $2.5 million Western & Southern Open tennis event.

The world No. 1 stalwart leveled former top-ranked star Jelena Jankovic 6-1, 6-3 in 58 minutes on the hardcourts at Lindner Family Tennis Center.

The Serbian Jankovic titled here in 2009 and was the Cincinnati runner-up in 2011.

Williams is now 10-4 lifetime against Jankovic, including a win in Dubai earlier this season.

The 17-time Grand Slam titlist Williams was last year's Western & Southern Open runner-up to Victoria Azarenka, who lost to the American great in the last two U.S. Open finals.

Williams' semifinal opponent on Saturday will be another former No. 1, 12th- seeded Dane Caroline Wozniacki, who posted a Day 5 upset by taking out fourth-seeded Polish star Agnieszka Radwanska in straight sets, 6-4, 7-6 (7-5). The former U.S. Open runner-up Wozniacki is now 5-5 all-time versus the former Wimbledon runner-up Radwanska, who was last week's titlist in Montreal.

Williams and her good friend Wozniacki will meet for the second time in two weeks, as the American stopped the Dane in a quarterfinal in Montreal last week. Williams is 7-1 lifetime versus Wozniacki, including wins in their last four meetings.

The 2014 Cincy champion will collect $467,300.