ST. PETERSBURG, Russia -- Five-time Grand Slam champion Maria Sharapova is forced to withdraw from the St. Petersburg Ladies Trophy due to a right shoulder injury.

The former World No.1 was due to contest a hotly anticipated second-round match against No.3 seed Daria Kasatkina, which would have been the second meeting between the two highest-ranked Russians on the WTA.

Unfortunately for the current World No.29, the shoulder ailments which have plagued her during recent years made moving forward in the St. Petersburg event untenable. Sharapova therefore is still looking for her first quarterfinal at Premier level or above since the French Open last year. Kasatkina makes the quarterfinals via walkover.

“I tried to do everything possible to be able to be ready to compete this week, but my right shoulder continues to be an issue for me," Sharapova said. "I will meet with my team of doctors over the next few days to evaluate the situation, and I look forward to returning to completion as soon as possible.

"It was so special to play in front of my home crowd this week and I wish I could have continued competing in this fantastic tournament.”

Kasatkina thus moves into the quarterfinals of the Premier event without having played a match, and, indeed, is still seeking her first match win of 2019. The World No.12 will meet either No.5 seed Julia Goerges of Germany or Russian wild card Vera Zvonareva, the former World No.2, in the elite eight.

Sharapova was playing in St. Petersburg for the first time, and started the event strongly with a two-set victory over Daria Gavrilova of Australia.

"I know when I play at home, I am strongly and warmly supported by the fans. For me it means a lot to win a match in homeland after so many years," Sharapova said after that victory.

The Russian superstar was also able to visit the Hermitage Museum and the Mariinsky Theater in the seaside city ahead of her opening-round encounter against Gavrilova.