NEW YORK, NY, USA - It looked like trouble for Maria Sharapova as Jarmila Groth overpowered her in the first set, but one of the biggest fighters out there had come equipped, got a grip and buckled down for a 46 63 61 first round win.

Sharapova, the No.14 seed, was facing one of the most improved players on the circuit - Groth had reached the fourth round of the last two majors and has looked fitter than ever, and won the battle of big groundstrokers in the first set.

Groth had never beaten a Top 20 player before, though, going 0-15, and winning only two sets in those 15 matches. Sharapova seemed to sense that and her confidence only grew, as she defied her previous results after losing the first set at a Grand Slam - she was 88-5 after winning the first set, 9-21 after losing it - and beat the hard-hitting, Slovak-born Australian handily in three.

"She really swung and didn't give me much time to do anything out there," Sharapova said of the first set. "Against a player like that, who plays the 1-2 punch type of tennis, it's quite difficult to get a rhythm in the beginning, but I just hung in there. I knew it wasn't over. I knew I still had my chances."

Sharapova wasn't the only former US Open champion to go three sets on a muggy Tuesday, as No.11 seed Svetlana Kuznetsova beat Kimiko Date Krumm, 62 46 61. The former world No.4 turns 40 in a month but is still a force to be reckoned with, a few weeks ago breaking back into the Top 50.

Earlier in the day, No.4 seed Jelena Jankovic and former phenom Mirjana Lucic, a qualifier here, set up a second round clash. Read more here.

Other notable seeded winners were No.7 seed Vera Zvonareva, No.9 seed Agnieszka Radwanska and No.15 seed Yanina Wickmayer. The first set of upsets took place as well, with No.8 seed Li Na, No.17 seed Nadia Petrova, No.26 seed Lucie Safarova and No.30 seed Yaroslava Shvedova all going down on Day 2. Li was ousted by Kateryna Bondarenko, a quarterfinalist here last year, 26 64 62; Petrova was edged by Andrea Petkovic in a match between the No.1 and No.4 ace leaders so far this year, 62 46 76(4).

In the final match of the night, No.1 seed Caroline Wozniacki got past American wildcard Chelsey Gullickson in a match that started just before midnight, scoring a 61 61 win. It was Wozniacki's 14th straight win in the first round of a major, her only loss at this stage coming in her very first major at the French Open in 2007 (to the now-retired Nathalie Dechy in three sets).