Svetlana Kuznetsova believes opponents fear her more because of the renewed grit and determination she shows under pressure.
Kuznetsova was the last player to secure her place at the WTA Finals, beating out Johanna Konta by winning the Kremlin Cup in her native Russia last weekend.
She has won her opening two matches in Singapore against Agnieszka Radwanska and Karolina Pliskova in three sets, the latter a 3-6 6-2 7-6 (8-6) on Wednesday, and she believes her increased resilience is proving key.
"I play with my heart - I always did ... but some things are just starting to work right now. Maybe I start to believe a bit more and I just hang in there more," said Kuznetsova.
"Some things come together and you get confidence and I see opponents fearing me more than before because I win matches, I fight. It doesn't matter if I play like c**p and I'm sore, I'll just be there.
"It's the last matches of the year and my year has been quite good compared to the last five seasons, especially with winning two matches in the championships for the first time in my career - it's like a miracle because normally I was like, 'Jesus, round robin again'.
"This year I came and said whatever I just play each match. I already appreciated being here because it was at the last moment."
Pliskova admitted she felt the effects of a draining three-set match in her shoulder, adding that it is tough to compete with an opponent who is as confident as Kuznetsova.
"I think the first set the serve was okay and then I just didn't find my rhythm. I took off the speed a little bit and I felt a little bit [of discomfort in] my shoulder, so that's why maybe the first serve was not that fast and not that good," said Pliskova.
"She has a different game. She is right now playing some of her best tennis - you saw it the last two shots she played. That title in Moscow probably helped her a lot.
"She's feeling confident and it's always tough to play someone like this. I just think it was so close, though, there was not that many bad things that I did wrong."