INDIAN WELLS, California (Reuters) - Maria Sharapova fell victim to an emotional Flavia Pennetta, who burst into tears before regaining her composure to stun the second seed 3-6, 6-3, 6-2 at the BNP Paribas Open on Tuesday.

Italy's Pennetta, the defending champion at Indian Wells, left the court momentarily after breaking down following her first-set loss.

"Sometimes, women have these moments. (I) just go and let everything out, screaming... " she told reporters.

"I just breathe and just let it pass."

When the 15th seed returned, she seized the momentum, going on to win 10 of the last 13 games to blaze past the two-time champion Sharapova and into the last eight.

Sharapova said she was unaware of Pennetta's emotional outburst and had struggles of her own, with the Russian finishing with 42 unforced errors and 11 double faults.

"Maybe I wasn't playing my best tennis but I was competitive enough," Sharapova said. "I just wasn't able to step up in the key moments."