The Russian superstar eased to a 6-2, 6-2 win over Hungary's Melinda Czink in her first match since finishing with a silver medal at the Olympics.
Sharapova then pulled out of the Montreal and Cincinnati tournaments with a stomach problem which left her in severe pain as well as her head in a spin after undergoing an ultrasound examination.
"It was really weird. They told me I was fine, not pregnant. I'm like, 'Can I get my money back?'" smiled the 2006 US Open champion.
"It was worse when I got to Montreal. At the end of the day, I think it was some stomach bug. But I thought it was getting better. Then I started eating like the normal Maria and it wasn't better.
"I don't think we should make this much more dramatic than it was. I mean, at the time I was being dramatic, but I'm fine. I was fine."
Sharapova, whose French Open win this year allowed her to complete a career Grand Slam, also faced down another inquiry into her private life -- over whether or not she and her fiance, ex-NBA basketball star Sasha Vujacic, would be marrying in Istanbul in November.
"I don't have a wedding coming up in November. That's not true. I'm so surprised everyone believed that," she said.
Sharapova sent down 24 winners to Czink's eight in a dominant display on Arthur Ashe Stadium court, where a dropped service game in the fourth game of the second set was her only blemish.
She then revealed that the brand new Audi car, given to her by Russian President Vladimir Putin for being an Olympic medallist, had been gifted to her father, Yuri.
"My dad stole it," joked Sharapova. "I got the medal, he's got the car. It's too tough to ship it from Russia. The medal is easier to transfer."
Sharapova will next face Spain's Lourdes Dominguez Lino for a place in the last 32.
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