Tennis: It's Azarenka v Jankovic, Williams v Li in Cincinnati Masters semi-finals

Victoria Azarenka of Belarus hits a return ball to Caroline Wozniacki of Denmark during their quarter-final round match at the Cincinnati Open tennis tournament in Cincinnati, Ohio on Friday, Aug 16, 2013. Azarenka defeated Wozniacki 6-3, 7-6 (7-5) o
Victoria Azarenka of Belarus hits a return ball to Caroline Wozniacki of Denmark during their quarter-final round match at the Cincinnati Open tennis tournament in Cincinnati, Ohio on Friday, Aug 16, 2013. Azarenka defeated Wozniacki 6-3, 7-6 (7-5) on Friday to reach the Cincinnati Masters semi-finals against Jelena Jankovic. -- PHOTO: REUTERS

CINCINNATI, Ohio (AFP, REUTERS) - Victoria Azarenka defeated former No. 1 Caroline Wozniacki 6-3, 7-6 (7-5) on Friday to reach the Cincinnati Masters semi-finals against Jelena Jankovic.

Second seed Azarenka came from a break down in the second set before advancing on her third match point in the tiebreaker against her Danish opponent. The win was only the third in nine meetings for Azarenka against Wozniacki.

Jankovic booked her spot as she beat Roberta Vinci 6-0, 6-4.

They joined world No. 1 Serena Williams in the final four.

The 31-year-old American was at her lethal best as she crushed Romanian Simona Halep 6-0, 6-4.

Williams will meet defending champion Li Na of China, who received a walkover into the last four when Poland's Agnieszka Radwanska withdrew from the tournament to attend her grandfather's funeral.