Australia's Samantha Stosur reached the WTA Tournament of Champions semi-finals on Friday with a 6-1 6-4 win over Bulgarian wildcard Tsvetana Pironkova.
Fourth-seeded Stosur will face Russia's Anastasia Pavlyuchenkova for a place in the final, while Saturday's other semi-final will feature former world No.1 Ana Ivanovic against in-form Romanian Simona Halep, who has five titles to her name this year.
"I definitely got a lot tighter as the match went on," Stosur said.
"I got off to a great start, then a tough service game trying to serve out the set. Thankfully, I got through that, then it was a matter of holding serve from there. I got the break in the second set and managed to close it out, so I'm happy.
"It's been great to be able to carry on from the last three or four weeks. To come here, the last event, to finish the group on top, hopefully I can continue the momentum in the semi-finals."
Pavlyuchenkova, seeded sixth, accounted for French No.7 seed Alize Cornet 6-2 6-2.
Ivanovic, the world No.16 and second seed, made it to the last four despite losing her last group match 6-4 3-6 7-6 (7-1) to Russia's No.5 seed Elena Vesnina.
Ivanovic, a French Open winner, had led 5-2 in the final set.
The 22-year-old Halep made the semi-finals by winning all three group matches without conceding a set and dropping just 16 games.