Sanchez Vicario says world No. 1 Osaka facing pressure of instant fame

Tennis - WTA Premier 5 - Italian Open - Foro Italico, Rome, Italy - May 17, 2019 Japan's Naomi Osaka during a press conference after withdrawing from her quarter final match against Kiki Bertens of Netherlands due to injury REUTERS/Matteo Ciambelli

BENGALURU (Reuters) - Naomi Osaka's fluctuating form before the French Open is a sign that the newest star in women's tennis is struggling with the pressure of being number one, Spanish tennis great Arantxa Sanchez Vicario said.

Osaka, 21, took the tennis world by storm when she beat Serena Williams in the U.S. Open final last September and claimed a second successive Grand Slam title at this year's Australian Open to become the first Asian player to top the singles rankings.