But that did not mean there was no form among the remaining quarter-finalists. She became the first teenager since Serb Ana Ivanovic in 2007 to reach the last four at Roland Garros. Also, she can change the rhythm and everything.
Wozniacki has had a tougher run through the French Open, and doesn't appear to be quite at full fitness.
Nadal is a nine-time champion at Roland Garros.
Ostapenko found a way through, though, and broke twice for a historic win!
Both Ostapenko and Bacsinszky, the 30th seed, will celebrate their birthdays when they meet on Thursday (June 8).
Bacsinszky made the last four in Paris in 2015, losing to eventual champion Serena Williams of the US. Trailing 5-4, Wozniacki broke the teenager to love when Ostapenko sprayed three errors and double-faulted at 0-40 and the former U.S.
She held to force Bacsinszky to serve it out, and the Swiss was equal to the task, ensuring she gets to play in the semi-finals tomorrow - her birthday.
She was playing her third consecutive French Open quarter-final on Tuesday and is now into her second semi in three years. Her winning smile at the end of today's victory says yes.
But there were twists and turns aplenty as the stormy skies over Paris took centre stage.
Both had to endure winds whipping up dust in their eyes during their respective ties.
She is the youngest French Open semifinalist in a decade.
Next came perhaps the game of the match, a 12-minute triumph of quality and touch over adversity. Her forehand fell apart in the fourth game as a pair of netted forehands gave Mladenovic the break and a 3-1 lead.
In the second set, one disruption-a medical emergency in the crowd-was followed by more.
Bacsinszky started the better of the two players after the start of the match was delayed by heavy rain.
When they returned, Mladenovic raced into a 3-2 lead.
But the Latvian, who is a chasing a first career title, hit back impressively with three breaks of serve in the second set to level the match.
"The one thing we did when Ivan [Lendl, his coach] got here, we went right back to the basics", said Murray yesterday.
"We had a hurricane, a sandstorm and nearly snow", she said before adding that coming from Switzerland, it wasn't hard to adapt.
"I think she managed to play way better than me", Mladenovic said.
Bizarrely. Bacsinszky's birthday is on the same day and Ostapenko also played doubles with the Swiss in China past year.
"I practiced in Bienne a few weeks ago with (Swiss player) Victorija Golubic and it was snowing".
"Yeah, it's pretty amusing we have the same birthday". "I think it's pretty cool... I woke up at 4:00", she told a news conference. I'm really happy to be through to my second semi-final here. "I'm no longer feisty". "And I think the courts I play are much bigger".
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