Jelena Ostapenko presented herself with the perfect 20th birthday gift by reaching a first French Open final after blasting past Switzerland's Timea Bacsinszky on Thursday.

The Latvian became the first Grand Slam finalist from her country as she overpowered 30th seed Bacsinszky 7-6 (4), 3-6, 6-3 in the last four at Roland Garros. She will face Romanian third seed Simona Halep, the 2014 runner-up, for the title on Saturday who beat Karolina Pliskova 6-4, 3-6, 6-3 in the other semifinal.

"I'm really happy to be in the final, especially on my birthday. I think it's a nice gift," said Ostapenko, whose win was greeted by the crowd singing 'happy birthday'.

The world number 47 is the first unseeded player to reach the final in Paris since Mima Jausovec in 1983.
Ostapenko is also the youngest woman to advance to the final of a major since a 19-year-old Caroline Wozniacki finished runner-up at the 2009 US Open.

Ostapenko fell in the first round on her main draw debut in Paris last year but is one win away from becoming the first player since Gustavo Kuerten in 1997 to win their maiden tour-level title at a Slam.

Bacsinszky broke Ostapenko for an early 2-0 lead, but the Latvian took the challenge to Bacsinszky with her aggression, nipping ahead at 4-3 before the Swiss called for the trainer.

Bacsinszky complained of a problem above her right knee after jarring her foot in the clay and resumed play with her leg heavily taped.

Ostapenko faltered when she tried to serve it out at 6-5, but the Latvian took the tie-break with a swinging backhand volley.

She continued to let fly with a bombardment of winners and errors, but Bacsinszky pounced as the Latvian's radar misfired to break for 4-3 in the second set before Ostapenko gifted it to her with a double fault on set point.

Later, the third seed Halep, overwhelmed by Pliskova's power in the second set, regained the momentum in the decider, frustrating her second-seeded opponent with her ability to soak up punishment.