Elina Svitolina set out to "silence the haters" in Singapore this week and after rallying to claim the WTA Finals title with a 3-6 6-2 6-2 victory over Sloane Stephens on Sunday, the Ukrainian hopes her critics will remain muted.
Wozniacki knew only a straight-set victory would see her advance from the group stage but after taking the opening set, Svitolina assumed control to win the match 5-7, 7-5, 6-3 and progress to the final four.
Bertens saved one set point on her serve in the 10th game of the first set, but couldn't repeat that trick in the 12th game, double-faulting at 15-40 to surrender the set.
It was Svitolina's turn to make the initial breakthrough in the second set when she capitalised on untidy play from Stephens to edge a break ahead. I've played so well this whole week, and I cannot let this be the last match of the season.it can't end like that.
"I came out here a little bit nervous, and I wasn't really feeling the ball", Stephens said after the match on court.
"It's been a insane year, I think", Osaka told reporters after retiring from her final group match following the loss of the first set to Kiki Bertens on Friday. "Not the way I wanted to finish but I worked really hard to get here and I can be really proud of my results", she said.
"Then I lost that second game in the third set where I was just struggling a little bit but bounced back straightaway".
But Stephens clawed her way back and screamed when Pliskova's forehand went wide to give her a first game after just over 50 minutes of play.
Ukraine's Elina Svitolina celebrates after winning her semi final match againast Netherlands' Kiki Bertens.
But it was enough for Bertens to seal a final four spot in her debut at the season finale, having defeated top seed Kerber earlier in the round-robin phase.
Svitolina held another tight service game to stay alive in the opener, but Stephens sealed the set when her opponent could only find the net with a backhand.
The 24-year-old's momentum continued as she produced an astounding run down victor to break Stephens in the second game.
The 21-year-old Osaka, who started the year ranked No. 68 and is now at a career-high No. 4, beat Serena Williams in the U.S. Open final and watched as the 23-time Grand Slam champion argued with the chair umpire and was penalized for it. I wouldn't say confident but I'm more, like, I have inner peace.
Osaka had started the match brightly, rolling through her service games before being broken in the eighth game. Next year the tournament will be happening in the Chinese city of Shenzhen.