GUADALAJARA, Mexico - No.8 seed Anett Kontaveit continued her blistering form at the Akron WTA Finals Guadalajara on Tuesday night, defeating No.4 seed Maria Sakkari 6-1, 3-6, 6-3  to advance to the final in her tournament debut. The 25-year-old Estonian will face former No.1 Garbiñe Muguruza for the biggest title of her career on Wednesday.

Kontaveit is now a perfect 7-0 in semifinals this year and now finds herself on the verge of a third consecutive title and fifth overall, which would tie World No.1 Ashleigh Barty for the most this season. Currently ranked No.8, Kontaveit can finish the season at No.6 if she wins the Billie Jean King Trophy.

"I still can't quite believe that I'm even here and I'm playing against the best players at such a prestigious tournament," Kontaveit said. "I'm just so proud of myself that I managed to do this and so happy to be competing at this level and just trying to take it all in."

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Wednesday's final is a rematch of the final round-robin encounter in the Teotihuacán group, which Muguruza won 6-4, 6-4 to snap Kontaveit's 12-match winning streak. The Spaniard leads the head-to-head 3-2. This is the first time since 2016 WTA Finals that the finalists came from the same group. That year, Dominika Cibulkova defeated Angelique Kerber after losing to the German in group play. 

Kontaveit, who struck 32 winners, 15 more than her opponent, has now won 29 of her past 32 matches. Her victory over Sakkari is her tour-leading 39th hardcourt win of the season. She also ties Ons Jabeur for the most wins this season, posting a 48-16 record.

The loss drops Sakkari to 1-7 in semifinals this season.

Tale of the match: Kontaveit's ability to hold serve has been the story of her WTA debut. Coming into Tuesday night's match, she had been broken just twice over three matches - both coming against Muguruza in her final round robin match - winning 92.9% of her service games. That trend continued through a blistering opening set Tuesday, as Kontaveit powered through her service games without facing a break point while breaking Sakkari twice to take it 6-1 in just 27 minutes.

After a gritty hold to start the second set, saving two break points with clean forehand winners, Sakkari stayed level with Kontaveit. But Sakkari could not make inroads on the Kontaveit serve, which emboldened the Estonian in her own return games. Under pressure again on serve at 3-3, Sakkari saved break point to come through a five-deuce game and hold to 4-3.

With the help of six aces in the set, Sakkari scraped through her service games and finally earned her first break point after 70 minutes of play. With Kontaveit serving at 3-4, Sakkari made good on her only break point of the match and then held serve on her fourth set point to force the duo into their first deciding set in 12 meetings.

Turning point: Sakkari struck first in the final set, breaking Kontaveit to lead 3-2, but the Estonian struck right back to break at love. That began a run of eight consecutive points, after a love hold boosted Kontaveit to a 4-3 lead.

"I think the turning point in the third set maybe when I went a break down, 3-2, just managed to tell myself that if this is the last match of the season, then I might as well enjoy it," Kontaveit said. "I feel like I got some freedom from that and just started playing better and managed to turn that set around."

Serving at 4-3, Sakkari built a quick 40-0 lead before Kontaveit pulled her back to a protracted deuce game. In all, Sakkari had multiple opportunities to close the game, but Kontaveit stayed steady, finally earning her only break point of the game after saving eight game points and broke to 5-3.

"Serving on the game, I just saw the finish line," Sakkari said. "Things went downhill."

Kontaveit closed out the win with a hold, sealing her spot in the biggest final of her career after 2 hours and 2 minutes.

Kontaveit on her self-belief: "I feel like the last few months have really showed me that I can play really well, I can beat great players consistently," Kontaveit said. "I think I sort of have this self-belief now. When I came here, of course, I had nothing to lose. Every time I step on the court, I still think I can win the match, just do well."

A tough loss to swallow for Sakkari: "Today was a missed opportunity from my side," Sakkari said. "It's definitely from my side. Obviously there's a lot of respect from my side to Anett's game. I think today I was just very close to taking that chance. I just wasted it.

"That's why it hurts so much. It's not that it was just bad luck, it's that I threw away another chance. It hurts."