Holder Elina Svitolina will face world number one Ashleigh Barty in the end-of-season WTA Finals showpiece on Sunday after they got past Belinda Bencic and Karolina Pliskova respectively in the semi-finals at Shenzhen Bay Sports Centre.

Australian Barty beat second-seeded Pliskova 4-6 6-2 6-3 after grinding down the big-serving Czech on Saturday to seal her first appearance in the final of the tour championship.

Svitolina had earlier sealed her spot in a second straight final after Bencic retired midway through the third set due to cramp as she trailed 5-7 6-3 4-1, having forced the Ukrainian to drop a set for the first time in the tournament.

Pliskova put Barty's serve under real pressure early in the first set and that eventually paid off when the Czech broke the Australian in the fifth game before going on to claim the set.

But the top seed showed her tenacity in the second as she fought back, twice breaking Pliskova to take the match to a deciding set, where she overcame the Czech to secure her spot in the final, successfully converting on her second match point.

World No 1 Ash Barty will contest her first Tour Championship final

"I felt like that whole match was at an incredibly high level," said Barty. "I didn't do much wrong in the first set and I'm just really pleased to get another chance to play out here.

"(The final) is a match I have to come out here and enjoy. I've got nothing to lose and I need to come out and enjoy and try to end my regular season really well.

"It's an opportunity against an extremely tough player who knows how to win in these situations."

Svitolina responded in style after dropping the first set to claim the second before Bencic's fitness issues eventually saw the Swiss concede defeat and leave intact the champion's hopes of claiming the $4.75m first prize at the $14m event.

"When I was coming to this tournament, I was expecting very, very tough matches," said Svitolina.

"It's the last tournament of the season and tomorrow is the last match of the season, finally. It's going to be a tough one but I'm going to leave everything on the court to try to raise the cup again."

Bencic claimed the first set despite taking a medical time out following the penultimate game, breaking Svitolina's serve immediately after the resumption to take the lead.

It was the first set the Ukrainian had lost at this year's finals but she broke immediately at the start of the second set before setting up a decider by swatting Bencic's second serve into the far corner with contempt to level the scores.

The 22-year-old Bencic's struggles continued, however, and, with Svitolina winning four of the first five games of the third set, she conceded defeat to become the fourth player to withdraw from the tournament due to illness or injury this week.