Elina Svitolina is on a mission to silence the "haters" in Singapore after beating Petra Kvitova in her WTA Finals opener on Sunday.

Svitolina had not triumphed against Kvitova for four years and failed to take a set off the Czech in their previous five meetings but ended that miserable sequence in style, recording a 6-3 6-3 win.

The sixth seed felt light-headed immediately after the White Group match, though there was little sign she was struggling during an impressive performance on court.

Svitolina will be back in action against Karolina Pliskova, who beat Caroline Wozniacki in the day's other match, on Tuesday and is fuelled by a determination to show she belongs in the season-ending tournament.

"I'm just not feeling good," the world number seven told the media after her straight-sets triumph.

She added: "I was playing good today, you know, quite solid from the baseline and putting pressure on Petra today. This was the key for me."

"Winning this match definitely gives me lots of confidence. I want to take this as one to go forward, and for all those people and haters that were saying that I don't deserve to be here and I'm not good."

"Until the next match, I can really enjoy this win."

Kvitova was in great spirits despite starting her campaign with a defeat.

"Life makes me happy. I already said that I'm very proud of myself to be here and be part of this. I'm not depressed and just sitting and crying." said the two-time Wimbledon champion.