Former world number four Cibulkova announces retirement

The 30-year-old Slovakian claimed eight WTA singles titles and entered the top four in 2017.

Her biggest title came in 2016 when she defeated then world number one Angelique Kerber to win the WTA Finals.

Cibulkova, who has not played since the French Open, became the first Slovak woman to reach a Grand Slam singles final in 2014 when she lost to China's Li Na at the Australian Open.

She said she had made up her mind about retirement at Roland Garros. "It was strange because I knew, and no one around me except my team knew it would be my last tournament," she said.

"At that point, I was 100% sure. I wasn't doubting or thinking 'maybe yes or no.' I knew I wanted to do it like this, for this to be my last tournament. I went home and was happy with my decision.

"It's hard to make it, but once you do, you feel more free."

(Reporting by Martyn Herman, editing by Pritha Sarkar)