Ukraine's Marta Kostyuk serves the ball to to Spain's Paula Badosa (not in photograph) during their women's singles tennis match on the fifth day of the 2023 Wimbledon Championships at The All England Tennis Club in Wimbledon, southwest London, on July 7, 2023. (PHOTO / AFP)

LONDON - Ukraine's Marta Kostyuk reached the Wimbledon third round for the first time after her Spanish opponent Paula Badosa retired with an injury during their match on Friday.

The 21-year-old Kostyuk was leading 6-2 1-0 when Badosa pulled out with a back problem.

Badosa, the 25-year-old girlfriend of Greek Stefanos Tsitsipas who will renew his battle with Andy Murray later on Friday, missed the French Open due to a spinal stress fracture.

Badosa was scheduled to play with Tsitsipas in the mixed doubles but she has pulled out of the tournament saying the "smartest thing" to do was to stop playing.

ALSO READ: Tsitsipas, Badosa serve up romance

Spain's Paula Badosa serves to Ukraine's Marta Kostyuk (not in photograph) in a women's singles match on day five of the Wimbledon tennis championships in London, on July 7, 2023. (PHOTO / AP)

"The injury is the same as I have been struggling the past weeks. It's the stress fracture," Badosa told reporters.

"I tried my best to try to play here, but yesterday when I woke up I already, after my first-round match, felt it again.

"It's a little bit worse. So I will need a few days off and talk to my team and see what I do in the next days and the next weeks."

READ MORE: Kostyuk makes light of rain breaks to stun Sakkari

Kostyuk defeated eighth seed Maria Sakkari in the first round and will hope to continue her run against 25th seed Madison Keys.