Sharapova, a five-time Grand Slam winner, beat Daria Gavrilova of Australia 6-0, 6-4 to make the second round on Monday. She will next face her compatriot Daria Kasatkina. Sharapova had only met Kasatkina once when she won in straight sets in Montreal in August, reports Xinhua news agency.
Sharapova has rarely played the Russian tour events during her career, and when she has she's never got past the quarterfinals.
The No. 30 seed, who has been struggling since her return from a doping ban in 2017, was her ruthless self and powered her game with drive volleys, drop shots and lobs, opening the 2019 Grand Slam season at the Rod Laver Arena, reports Efe news.
The 22-year-old Briton Dart, who described Sharapova as her idol before the match, is 101 places behind her in the rankings and was playing in just her second Grand Slam main draw.
Sharapova had the 2-0 break within seven minutes, and shrugged off a detention for three deuces in the fifth game, and a time violation to hold for 5-0.
Dart got one breakpoint on her serve in the eighth game but Sharapova stormed back soon after.
"It's been many years since I won the trophy here," Sharapova said after the match, according to the event's official website.
"Despite my opponent not having the best day, I still had to get the job done today. I love what I do, I love competing and challenging myself to get better. The youngsters are coming up - but not yet," she added.
Sharapova will next play against Swede Rebecca Peterson, who beat Sorana Cirstea 6-4, 6-1.
The wild carded Sharapova was troubled by her serve, producing five double faults in the whole match, three of which came in the first set, reports Xinhua news agency.
After each broke once in the first two games of the first set, the second seed broke another two and hold her own two to take a dominant 5-1 lead.
Although Sharapova managed to take the seventh game in her service, Halep showed no mercy in the eighth when she served, winning five points in a row to close the first set.
"I think she played an incredible match, probably the best she's played against me in all of our previous meetings. And I wasn't as sharp," said Sharapova.
"She was hitting the ball consistently, not making a lot of unforced errors, her service percentage was quite high. She did all the right things."
Sharapova was trying to raise her level by strengthen attacking power. But it is obvious not her game as she was broken twice in the third and seventh games of the second set, due to too many unforced errors including two double faults.
As the same as in the first set, the Romanian star won the set in the eighth game when she served, snatching her first ever career victory over Sharapova.
Awaiting Halep in the quarter-finals is either 11th seed Agnieszka Radwanska of Poland or Daria Kasatkina of Russia.
She will next face Germany's Laura Siegemund in Sunday's final, reports Efe.
Sharapova looked headed for victory when she dominated the opening set with the loss of just four points on serve here on Saturday.
In the second and third sets, however, Mladenovic made the 30-year-old Russian pay for missing her first serve, winning the vast majority of her opponent's second-serve points to break her four times.
Despite the narrow defeat, the five-time Grand Slam champion showed little sign of rust throughout the tournament and even kept down her number of double faults relative to some tournaments in the past.
The organisers' decision to grant Sharapova a wildcard sparked controversy, with many players saying the Russian should have to earn her way back into the main draw of WTA events.
In Saturday's second semifinal, Siegemund used a strong drop shot and forehand to keep fourth-seeded Romanian Simona Halep off balance in a 6-4, 7-5 upset win.
The No.1-seeded Williams recorded a straight sets 6-3, 7-6(5) victory over the No.2-seeded Sharapova.
Going into the final, Williams was the favourite - not just because she was World No.1 and Sharapova No.2, but because she had won the pair's last 15 clashes, 12 of those coming in straight sets.
Early on in the match that pattern continued, with Williams breaking in the very first game and, after a short rain delay, grabbing a second break for 5-2.
Sharapova got one of the breaks back in the next game but Williams broke one last time to take the first set 6-3.
All of that went out of the window in the second set, as the top 2 players in the world held tightly to all of their service games, with absolutely no breaks of serve - Williams did have her chance to finish the match with Sharapova serving at 4-5, 30-40, the first match point of the night, but the Russian bludgeoned a forehand down the line for a winner and subsequently held that service game.
The tie-break was tight but Williams forged ahead, building a 6-4 lead, and after Sharapova fought off a second match point with another huge forehand down the line.
Williams had the match on her racquet, stepping up to the baseline to serve on match point No.3. There was a bit of a hiccup - she fired what looked like a massive ace out wide, and she even began celebrating, but the serve was called a let. But she regrouped and fired the exact same ace to finally close it out.
Williams came into the Australian Open tied with Evert and Navratilova for the second-most Grand Slam titles in the Open Era, but she now has the stand-alone second-most with 19. Steffi Graf has 22.
The 32-year-old has not played since pulling out of an event in her native Russia at the end of January and had a small operation in February, reports the BBC.
The two-time Roland Garros champion announced on Instagram that she would not be participating in the tournament, which begins on May 26.
"Withdrawing from the French Open today. Sometimes the right decisions aren't always the easiest ones," she posted. "In better news, I have returned to the practice court, and slowly building the strength back in my shoulder. I really miss you Paris, until next year," she added.
Sharapova, who won the French title in 2012 and 2014, returned to the tour in April 2017 after serving a 15-month ban for taking the banned drug meldonium.
She reached the quarter-finals of the French Open last year, losing 2-6, 1-6 to third seed Garbine Muguruza.
"How do you leave behind the only life you've ever known? How do you walk away from the courts you've trained on since you were a little girl, the game that you love - one which brought you untold tears and unspeakable joys - a sport where you found a family, along with fans who rallied behind you for more than 28 years? I'm new to this, so please forgive me. Tennis - I'm saying goodbye," she said.
Sharapova did not specify if her decision is with immediate effect. She last played at the 2020 Australian Open where she lost in the first round to Serbian 19th seed Donna Vekic.
Long-standing shoulder problems have resulted in the Russian hardly playing any matches over the past year. Sharapova said that a big indicator that it may be time to hang up her boots came during the 2019 US Open.
"Behind closed doors, thirty minutes before taking the court, I had a procedure to numb my shoulder to get through the match. Shoulder injuries are nothing new for me - over time my tendons have frayed like a string. I've had multiple surgeries -once in 2008; another procedure last year and spent countless months in physical therapy. Just stepping onto the court that day felt like a final victory, when of course it should have been merely the first step toward victory. I share this not to garner pity, but to paint my new reality: My body had become a distraction," she said.
Sharapova shot to fame when she won the Wimbledon in 2004 at the age of 17. She went on to complete a career slam -- winning all four Major titles -- when she won the French Open in 2012.
(IANS)