Romania’s Simona Halep will take on the unseeded Jelena Ostapenko for the French Open title after two outstanding semi-finals here on Thursday which showcased some of the best ball-striking and athleticism the game has to offer.

Halep, the third seed and considered a weak favourite in what was called the most open of French Opens, reached her second Roland Garros final by outmanoeuvring the second seed, Karolina Pliskova, to win 6-4, 3-6, 6-3. Ostapenko, the world No47, overcame Timea Bacsinszky of Switzerland 7-6, 3-6, 6-3 with a barrage of 50 winners, the last of which put the 20‑year‑old into her first grand slam final. She is the first Latvian player to achieve the feat.

There was more than a sense, when Halep came from a set and 5-1 down to win her quarter-final against Elina Svitolina of Ukraine on Wednesday, that the Romanian had survived the toughest moment she would face in the tournament. But the 2014 runner-up had to play well to cope with the easy power of Pliskova, the runner-up at the US Open last year.

Halep led 4-1 in the first set and though Pliskova hit back to 4-3, she broke again to move ahead. Pliskova hammered a series of winners to get the early break as she won the second set and looked confident when she recovered from 4-1 down in the third to get back on serve at 4-3. But Halep, who credits her coach, Darren Cahill, with her new positive attitude, did not panic. The Romanian dug deep and returned to her gameplan, getting the taller Pliskova on the move and hitting into space. It worked as she broke for 5-3 and she served out for a place in her second grand slam final. “It’s an amazing feeling right now,” Halep said. “I’m just happy. I don’t know what was yesterday, I just care about today. It was extremely tough.”

Simona Halep and Jelena Ostapenko reach French Open final – as it happened Read more

Victory in the final on Saturday would make Halep the world No1 for the first time in her career but first she will have to beat a woman who does not seem to know what pressure is. It is three years since Ostapenko won the junior Wimbledon title, since when she has taken time to mature, better known for her feisty attitude than her results. Until this fortnight, she had never been past the third round of a grand slam and she has yet to win a Tour title. Now she is one great day away from winning her first grand slam crown.

With the fearlessness only young players can truly show, Ostapenko bashed down winner after winner to defeat Bacsinszky in 2hr 24min. The Swiss, a semi-finalist two years ago, has the greater experience and more variety but for long periods of the match she was bludgeoned. Even when Bacsinszky fought back and levelled at 3-3 in the decider, Ostapenko never wavered from her all-or-nothing approach and she pulled away to become the first unseeded woman to reach the final since Mima Jausovec in 1983.

Facebook Twitter Pinterest No3 seed Simona Halep (left) defeated No2 seed Karolina Pliskova in the second semi-final. Photograph: Alfonso Jimenez/REX/Shutterstock

Both players were celebrating their birthday on the day of the match but Ostapenko will probably remember it best. “When I came here, of course I didn’t expect I would be in the final,” Ostapenko said. “But then, first match was a tough match as well, and I won it. I think it kind of gave me confidence. Then every match I was playing better and better and I got my confidence, and I think it works pretty well. She was playing pretty well, and I was telling myself that I have to still play aggressive but to be, like, smarter and to not make many unforced errors. And I think it helped me that I was still playing very aggressive.”

Bacsinszky said she regretted not taking some opportunities in the first set but for the most part was impressed at the outrageous hitting of Ostapenko.

“She’s 20, not afraid of anything,” Bacsinszky said. “She doesn’t measure maybe what she’s doing right now. She probably doesn’t care. Best example is the match point. I serve very well wide. She’s, like, hitting as hard as she can down the line from nowhere. It comes above the net and in the corner and, I mean, who tries that? Seriously? I mean, it’s like one out of 10. But she does it. So we’ll see if she does it at 28 years old.”

If Ostapenko wins the final on Saturday, she will not care too much about what happens when she is older.