STUTTGART, Germany (Reuters) - Russia's Anna Chakvetadze collapsed on court and retired from her first round match in Stuttgart on Tuesday, the third straight tournament she has pulled out of sick.

The 24-year-old world number 50, who collapsed in Dubai because of a gastro-intestinal virus and retired in Indian Wells this year, pulled out with the score against Zuzana Kucova at 6-1 5-7 4-4.

"I started the match feeling fine but I knew it (dizziness) was coming and started to feel worse in the second set. It was the same feeling as the last two times," the former world number five said in a statement, adding doctors had cleared her to play.

"I don't have anything more to update at the moment. I saw the doctors at home before the tournament and they said everything would be okay which is why I decided to play here."

"But now it's the third tournament in a row that I have had to retire with this problem. It seems like the doctors don't have all the answers yet so I have been told to rest and we will see what happens. Hopefully we will find a solution."

(Writing by Karolos Grohmann; editing by Ed Osmond; To query or comment on this story: sportsfeedback@thomsonreuters.com)