Swiatek entered the semi-finals carrying a 15-match winning streak in Doha, having clinched the title in each of the last three editions.

The five-time Grand Slam champion was looking to become the first player since 2011 – and just second this century – to win the same WTA tournament four years in a row but Ostapenko had other ideas.

Ostapenko, the 2017 Roland Garros champion, became the first player to defeat Swiatek on five occasions.

The world number 37 fired 24 winners against just 15 unforced errors, brushing aside the second-ranked Pole after just 70 minutes of play.

Ostapenko is through to the third WTA 1000 final of her career and is searching for her first title at that level, having lost on her two previous attempts in Doha 2016 and Miami 2018.

Amanda Anisimova defeat Ekaterina Alexandrov

She will face Amanda Anisimova in Saturday's championship match after the American defeated Ekaterina Alexandrova 6-3, 6-3 to reach her second WTA 1000 final.

"I feel like this court has a special energy and it was always helping me. Everything started for me on this court (when I reached the final in 2016)," said Ostapenko.

"Today when I went on the court I was pretty confident that I could beat her because we played a lot of matches and I kind of know how to play against her. I was just focusing on myself and knew what I had to do. I'm really happy with the way I'm handling my emotions this week and I'm so happy to be in the final."

A blistering start from Ostapenko saw the Latvian unleash a forehand winner to break Swiatek in the opening game of the contest and she surrendered just one point on her way to a 2-0 lead.

Ostapenko got her hands on three set points on the Swiatek serve at 5-3 and converted her third opportunity to scoop the first set in 35 minutes.

The start of the second set followed a similar pattern to the first, with Ostapenko punishing Swiatek's serve, and attacking any short ball that came her way.

As the match clock hit one hour, Ostapenko was already up a set and 4-0 and cruising. Swiatek halted the momentum by getting one of the breaks back but her comeback attempt was short-lived as she dropped serve again the following game en route to a hefty defeat.

- 'Knew what to expect' -

Ostapenko limited Swiatek to under 50 percent in points won behind the first or second serve and logged seven return winners against the Pole.

"Obviously I was preparing for the match, and I pretty much knew what to expect from her," said Ostapenko of her success on return against Swiatek.

"I don't know, sometimes I know where the ball's coming, but sometimes I'm just going with my feelings and my instincts, so that helps me."

Another streak was broken on Friday as Anisimova, 23, ended Alexandrova's eight-match unbeaten run to advance to the final.

Alexandrova ousted two top-five players in Aryna Sabalenka and Jessica Pegula on her way to the Doha semi-finals, and was coming off of a title run in Linz earlier this month.

Anisimova broke twice to open up an early 4-0 gap and it took Alexandrova 22 minutes before she finally got on the board.

The big-hitting American bagged the opening set in 43 minutes and built a 4-1 lead in the second before securing passage to the fifth WTA final of her career.

Anisimova saved nine of the 10 break points she faced during the match to set up an all-unseeded showdown against Ostapenko.