MELBOURNE, Australia -- Maria Sharapova barely missed a beat in her first match back in Melbourne since a failed doping test in 2016 resulted in a 15-month ban from tennis.
One of just two former champions in the women's draw, Sharapova recovered from an early break in the second set and closed out her 6-1, 6-4 victory over Tatjana Maria with an ace at Margaret Court Arena.
She celebrated by twirling, waving and blowing kisses to the crowd.
"It's been a couple of years since I've been back here -- obviously I wanted to enjoy the moment," the 2008 Australian Open champion and three-time runner-up said in an on-court TV interview. "It was really meaningful for me to be out here."
Angelique Kerber, the 2016 champion, continued her resurgent run with a 6-0, 6-4 win over fellow German Anna-Lena Friedsam. It extended her streak to 10 consecutive wins, including the Sydney International title last week -- her first title since the 2016 US Open.
Her ranking slid into the 20s in 2017, but she's coming back into the kind of form that makes her a title contender.
"I'm just enjoying it on court again," Kerber said. "Something is going on with Australia and me. I love this country -- I enjoy my stay, play my best tennis."
Wimbledon champion and third-seeded Garbine Muguruza started her quest for the No. 1 ranking with a 6-4, 6-3 win over Jessika Ponchet, a player ranked 253 spots below her.
Madison Keys also reversed a trend, becoming the only one of the four American women who contested the US Open semifinals last September to reach the second round in Australia.
Kvitova double-faulted on match point, two points after hitting a half-court volley into the net. She had earlier saved three match points in the 10th game of the final set.
Last year during the Australian Open, Kvitova was recovering from surgery to her left hand as a result of a knife attack from an assailant who broke into her home in the Czech Republic in late December, 2016.
Kvitova, the 27th-seed player this year, was a semifinalist in Australia in 2012 and also made the quarterfinals in 2011.
No. 17-seeded Keys, the runner-up at the US Open, had a 6-1, 7-5 win over Wang Qiang.
Halep was in serious trouble twice -- having to save set points at 5-2 down in the first set, and badly twisting her left ankle early in the second -- before beating 17-year-old Australian wild-card entry Destanee Aiava 7-6 (5), 6-1.
"It's always really cool to go up against the best in the world," Bouchard said. "You use it as a measuring stick. I want to try to play my game and go out there and do some damage."
Sharapova was banned for 15 months after testing positive for the drug meldonium here in 2016, when she reached the quarterfinals, and finished last year ranked No. 60.
The five-time major winner could next meet No. 14-seeded Anastasija Sevastova, who beat her at the US Open last year in her return to a Grand Slam tournament.
After returning in New York, Sharapova is confident she has prepared again for a major.
"I felt like I have got a lot of things out of the way physically and emotionally and mentally last year with -- there was a lot of firsts again for me, playing the first tournament, first Grand Slam, and just different feelings and what it would be routinely," she said. "But it felt pretty routine today."
Information from The Associated Press was used in this report.