Jelena Ostapenko will meet Timea Bacsinszky on their birthdays in the semi-finals of the French Open after the teenage surprise package fought back to beat Caroline Wozniacki in a hugely rain-affected match on Tuesday.

The unseeded Ostapenko will face Swiss Bacsinszky in an unlikely last-four encounter when she turns 20 on Thursday following a 4-6 6-2 6-2 defeat of the former world number one on Court Suzanne Lenglen.

Ostapenko had never been beyond the second round of a grand slam before the Australian Open this year, but can now look forward to the biggest match of her life on her first day in the 20s after becoming the first Latvian woman to reach the semi-finals of a major.

The world number 47 from Riga has not won a singles titles on the WTA Tour in her fledgling career, yet is only two victories away from lifting the Coupe Suzanne Lenglen after her positive approach paid off.

Ostapenko will aim to give herself the best present she could wish for and spoil Bacsinszky's 28th birthday later this week.

Eleventh seed Wozniacki's wait for a first grand slam continues on after she was dumped out six hours after the quarter-final started as poor weather led to one lengthy delay at the end of the second set and another soon after the players had resumed.

A string of unforced errors from Ostapenko gifted Wozniacki a commanding early lead, although the Dane did need to save five break points on her way to establishing a 5-0 lead.

If Ostapenko's aggressive style of play initially appeared ill-suited to the gusty conditions, it was not long before she found her feet, winning four games in succession.

Having worked so hard to get back into the set, Ostapenko then threw in a shocking service game and was broken to love, handing Wozniacki the opening set.

However, the youngster was able to seize the advantage in set two, moving a double-break up at 5-2 before play was suspended.

Ostapenko wasted no time in wrapping up the set when play resumed after a long wait due to the weather and Wozniacki saved a break point to take a 2-1 lead in the decider before the heavens opened again.

When the sun came back out and the covers were removed again the underdog broke a more cautious Wozniacki to lead 3-2 and continued to go for glory, an approach which worked a treat as she reeled off five games in a row, forcing a decisive error from Wozniacki with a vicious backhand.