Latvia's Jelena Ostapenko celebrates winning her semi final match against Switzerland's Timea Bacsinszky at French Open at Roland Garros, Paris, France on June 8, 2017. [Photo/Agencies]

Both players celebrated their birthdays on Thursday, with Ostapenko turning 20 and Bacsinszky turning 28.

The underdog Ostapenko also became the first Latvian ever to have reached the final at a Grand Slam tournament.

After sharing the first six games into the match, the Latvian broke to build a 4-3 lead after the seventh game.

Bacsinszky appeared to injure her right thigh muscle when she went out for a return. She called for a medical timeout during the interval, before returning to the court with heavy bandage on her thigh.

"It's not a tear. It's just muscle soreness, probably," explained Bacsinszky. "It was a sharp pain at the beginning, but then I got some painkillers, and I got the tape that I have had on was helping me quite a lot."