Updated

Indian Wells, CA (SportsNetwork.com) - Two-time champion Serena Williams had to overcome Sloane Stephens in order to reach the quarterfinals at the $5.3 million BNP Paribas Open.

The world No. 1 Williams dropped the opening set in a tiebreak before charging back to stop her fellow American and complicated rival Stephens 6-7 (3-7), 6-2, 6-2 in just over two hours at the beautiful Indian Wells Tennis Garden.

Williams swatted 14 aces, but also piled up nine double faults, while breaking Stephens six times, compared to only two breaks for the loser.

The 33-year-old Williams is now 3-1 lifetime versus Stephens, and Tuesday marked their first meeting since 2013. The one win for Stephens was a big one, coming in the quarterfinals of the Australian Open that year. But things turned sour for Stephens after that run to the semifinals in Melbourne. In an interview published in May that year, Stephens said Williams had completely ignored her after the loss, and their relationship has never quite been the same.

Williams, playing here for the first time in 14 years, was the Indian Wells champ back in 1999 and 2001.

Defending-champion and 15th-seeded Flavia Pennetta, who defeated Agnieszka Radwanska in last year's final, upset second-seeded Maria Sharapova 3-6, 6-3, 6-2 in a match that lasted just over two hours.

Sharapova titled here in 2006 and 2013 and was the runner-up in 2012.

Meanwhile, No. 3 seed Simona Halep knocked out 14th-seeded Karolina Pliskova 6-4, 6-4, Lesia Tsurenko knocked off sixth-seeded Eugenie Bouchard 6-7 (5-7), 5-7, 6-4, 12th-seeded Carla Suarez Navarro drove out Heather Watson 7-6 (7-5), 3-6, 6-1, 18th-seeded and 2010 Indian Wells champion Jelena Jankovic dropped No. 31 seed Belinda Bencic 6-3, 3-6, 6-3, 24th-seeded Sabine Lisicki downed No. 25 seed Carolina Garcia 6-4, 6-4 and No. 27 seed Timea Bacsinszky topped 23rd-seeded Elina Svitolina 4-6, 6-1, 6-1.