JOIN USAustralian Open champion Caroline Wozniacki continued her sensational start to the season beating two-time Grand Slam winner Angelique Kerber in three sets on Friday.
Wozniacki won 7-6 (7/4), 1-6, 6-3 to progress to the semifinals in a high-quality contest lasting almost two-and-a-half hours.
The Dane is also assured of holding on to her world number one spot after her main challenger Simona Halep pulled out of the tournament earlier in the evening because of a foot injury.
By advancing to the semifinal, Wozniacki becomes just the fourth woman in history to pass $30 million in tennis prize money.
Wozniacki hit 46 winners in a match free of controversy after the previous night when the Dane complained about her opponent Monica Niculescu's grunting. She will play Petra Kvitova who advanced after Julia Georges was forced to retire through injury when she was 4-6, 1-2 down.
Spain's Garbine Muguruza is through to Sunday's final -- and will get a day's rest because of the withdrawal of Halep -- after beating France's Caroline Garcia 6-3, 1-6, 6-4.
Nishikori survives
Japan's Kei Nishikori survived his toughest test since his return to the ATP Tour, having to come from behind to beat Radu Albot 4-6, 6-3, 6-1 on Friday to reach the semifinal of the New York Open.
Nishikori will now face South African Kevin Anderson who overcame American Frances Tiafoe 6-3, 5-7, 6-4 in a two-hour battle.
In earlier matches, second seed Sam Querrey topped Croatian Ivo Karlovic 7-6(5), 7-6(4).
He will meet Adrian Mannarino in the other semifinal after Mannarino overcame Spain's Adrian Menendez-Maceiras 7-5, 2-6, 6-3.