"I'm really happy, I love to be here", Ostapenko, the youngest woman to reach the French Open final since Ana Ivanovic in 2007, said after former Wimbledon champion Marion Bartoli and the crowd serenaded her with a chorus of "Happy Birthday".
Ostapenko blazed a trail into the final with a 7-6 (4) 3-6 6-3 victory over Swiss Timea Bacsinszky in a battle of the birthday girls.
"I m not ashamed to say that she played better".
"In the third set I just wanted to stay playing aggressive". Ostapenko powered her way to a 7-6 (7/4), 3-6, 6-3 victory to make history as the first Latvian grand slam finalist and the youngest at any grand slam since Caroline Wozniacki in NY eight years ago. For Halep to become number one she would have to win today's match and Saturday's final.
The contest between Hales and Pliskova lasted for two hours.
"Coming into this tournament, there were a few people who told me, "you have to be in the final to be number one".
Halep's hopes of reaching a second French Open final were dashed after she lost to Maria Sharapova in 2014.
Less than a month after fearing that she'd broken her ankle, Simona Halep is one match away from winning her first Grand Slam title.
The 47th-ranked Ostapenko, the first Latvian player to reach a Grand Slam final, won 7-6 (4), 3-6, 6-3.
Bacsinszky needed strapping added to her right thigh at 4-3 in the first set but it did not seem to affect her movement. The Romanian broke serve in the third game and benefited from 24 errors by her foe to claim the first set. Instead of meekly losing her last game, the Romanian showed she could fight like a tiger.
Even Djokovic found it hard to fathom how far he's fallen, only a year removed from leaving Roland Garros as a player nonpareil, the first man in almost a half-century to win four consecutive Grand Slam titles.
Among the four men's semifinalists at the French Open, Gustavo Kuerten picks Rafael Nadal to win a record 10th title in Paris. She has hit more backhand winners in the tournament than she has hit with her forehand, and if her backhand is stronger than Ostapenko's forehand, Bacsinszky has an excellent chance of making it to the championship match. Bacsinszky knew more than most what to expect, having played doubles with her a couple of times on Tour.
The 20-year-old Ostapenko will face the 25-year-old veteran Halep in the finals.
"It's going to be a very different match than today, it's going to be like playing the ball machine", Halep, who leads Pliskova 4-1 in head-to-heads, said.