ORDER OF PLAY
Play starts at 4pm
Barbora KREJCIKOVA (CZE) / Katerina SINIAKOVA (CZE)  v Ashleigh BARTY (AUS) / CoCo VANDEWEGHE (USA) or Kristina MLADENOVIC (FRA) / Timea BABOS (HUN) 
Not before 7.30pm
Elina SVITOLINA (UKR)  v Sloane STEPHENS (USA) 
Svitolina is unbeaten in Singapore, defeating Petra Kvitova, Karolina Pliskova, and Caroline Wozniacki in the round-robin stage, then Kiki Bertens in the semifinal.
This is the biggest final of Svitolina's career. Her best-ever Grand Slam result has been reaching the quarterfinals of Roland Garros in 2015 and 2017, and the Australian Open in 2018.
Svitolina was the first Ukrainian to qualify for the WTA Finals in singles when she made her debut appearance in Singapore in 2017.
Last year, she went 1-2 in the round-robin stage, failing to progress despite beating World No.1 Simona Halep in straight sets.
Sloane Stephens is also unbeaten in Singapore, having got past Karolina Pliskova, Angelique Kerber, Kiki Bertens, and Naomi Osaka to reach the final.
This is Stephens's debut at the WTA Finals, although she was the second alternate in 2013 - but did not play.
The last debutante to win the event was Dominika Cibulkova in 2016.
Elina Svitolina discussed seeing her mental development in action at the BNP Paribas WTA Finals Singapore presented by SC Global, where she reached the biggest final of her career over Kiki Bertens on Saturday.
SINGAPORE - Much as Elina Svitolina has had to rely on physicality through a week of long matches at the BNP Paribas WTA Finals Singapore presented by SC Global, the Ukrainian credits an improved mental toughness with helping her reach the biggest final of her career on Saturday.
“Every match here, starting from Kvitova, where I had to stay really, really strong, because I lost many times against her,” Svitolina said after outlasting Kiki Bertens in three sets. “It was the opening match and I definitely didn't want to start the same way as I started last year, so I had to be there and play my best game.”
After snapping a 12-set losing streak against Petra Kvitova, she survived another test against Karolina Pliskova and, in a full circle moment from last year, avenged a heartbreaking defeat against Caroline Wozniacki just to reach the semifinals.
Against Bertens, she shook off a second set tie-break to serve out the match from break point down.
“For me, that really showed that I can play great tennis in big stages. That's what matters for me. I think it's good step for me for the future and for the Grand Slams, as well.”
It’s an unlikely breakthrough for a player who, 10 days ago, was instead preparing to play at the Hengqin Life WTA Elite Trophy Zhuhai before learning she had, indeed, qualified for the WTA Finals following the results at the VTB Kremlin Cup in Moscow.
“When I qualified for this tournament, I definitely decided that I'm going to just go for it and that I'm good enough, I was going to trust my game, trust myself.
“Here I am in the final, so it's something that's really matters with me and really special moment for me, and I think definitely for the future it's something that I can be proud of.”
Svitolina cites the ability to adapt as key to her mental development, making small changes to her team in 2018 - parting with coach Thierry Ascione - and honing in on the right routines so she might be at peak performance whenever necessary.
“I always try to find something, something new, something fresh that can bring something into my game. The small things can make a difference. Sometimes, they're not gonna work, but you have to accept that and move forward.
“I'm convinced that if you learn from your mistakes, you always gonna find the right path and what's gonna work for you. It's very important to stay focused and be aware of what works for me. It's probably, because our season is very long and we have lots of different matches and different surface and different conditions, so you have to always adjust and be flexible.”
All of that was in motion against Bertens, who stayed within striking distance throughout the deciding set, but it was the former World No.3 who continued to adjust her way to the finish line.
“I was very happy the way I could come back and into the match after losing the second set where I had my chances. I lost that second game in the third set where I was just struggling a little bit, but then I bounced back straightaway. This, I think, made the big difference.”
For all the progress she’s made in Singapore, there’s still one match to go, one more opportunity for Svitolina to move forward ahead of the 2019 season.
“It’s definitely very special, but it will also be very special for the player who gonna be on the other side of the net. So I'm not alone, playing against myself. I'm going to be there tomorrow, try to play my best. That's definitely the last match of the season, so I'm just gonna leave everything on court.
“We'll see what the future holds.”
This article was first seen on www.wtatennis.com.