Angelique Kerber will have to find a way to end Simona Halep's hot streak in Cincinnati if she is to progress her bid to become the new world number one.
The German will tackle third seed Halep in the semi-finals of the Western & Southern Open after the pair secured respective victories over Carla Suarez Navarro and Agnieszka Radwanska in the last eight on Friday.
Kerber will replace Serena Williams - absent here due to a shoulder injury - at the top of the WTA rankings if she wins her next two matches - the final will feature either world number three Garbine Muguruza or rising star Karolina Pliskova.
Suarez Navarro gave Kerber a stern examination but the Spaniard could not resist when the fourth seed turned up the heat in the second set before closing out a 4-6 6-3 6-0 win. The in-form Halep, meanwhile, recovered from 4-0 down to stun Poland's Radwanska 7-5 6-1 in a little over an hour and a half.
Pliskova needed three sets to dismiss two-time grand slam winner Svetlana Kuznetsova 6-3 4-6 6-2 while French Open champion Muguruza dealt a 6-4 6-3 defeat to the last unseeded player standing, Timea Babos of Hungary.
Source: PA