American teenager Taylor Townsend came up a winner in her WTA debut, while former champion Daniela Hantuchova of Slovakia was tested in her first-round match at the $5.186 million BNP Paribas Open.
Townsend, a 16-year-old left-hander from Chicago, posted a 3-6, 7-6 (7-1), 6-3 victory over Czech Lucie Hradecka on the hardcourts at Indian Wells Tennis Garden. The top-ranked junior in the world at the end of 2012 will next face former world No. 1 Ana Ivanovic in the second round.
Hantuchova, who titled here in 2002 and '07, needed all three sets to get past French qualifier Stephanie Foretz Gacon, 6-3, 3-6, 6-4.
Two all-American matches went the distance, as Madison Keys defeated Melanie Oudin, 6-4, 4-6, 6-3, while Jamie Hampton earned a 5-7, 6-3, 6-1 comeback win over Bethanie Mattek-Sands, who was a finalist in Kuala Lumpur last week.
Swede Sofia Arvidsson overcame promising British lefty Laura Robson 2-6, 7-6 (7-2), 6-1, while additional wins came for Romanians Monica Niculescu and Irina-Camelia Begu. The hot Niculescu was a finalist in Brazil last week.
Meanwhile, 42-year-old Japanese veteran Kimiko Date-Krumm snuck past Kazakhstan's Galina Voskoboeva 6-4, 3-6, 6-4 and Poland's Urszula Radwanska doused Dutchwoman Arantxa Rus 6-3, 6-3 to set-up a second-round match with rising American Sloane Stephens, who's seeded 15th here.
In other first-round matches on Thursday, Stefanie Voegele, Alize Cornet, Garbine Muguruza and Kiki Bertens all advanced after dropping their first sets, while Mirjana Lucic-Baroni, Magdalena Rybarikova and Alexandra Dulgheru were straight-set winners.
Victoria Azarenka beat former champion and fellow former world No. 1 Maria Sharapova in last year's final in the California desert. The two women are this week's top seeds.
Other former Indian Wells champs in the field are former world No. 1s Caroline Wozniacki, Ivanovic and Jelena Jankovic.
This Premier Mandatory WTA event will pay its newest champion $1 million.