The 30-year-old German took the initiative from the first point, and rarely looked troubled as she saw off Sharapova in just over an hour, winning 6-1, 6-3, the first set taking 29 minutes, the second 35.

Sharapova is still on the comeback trail following the 15-month drug suspension she incurred in 2016, having returned to action in April last year.

But the way Kerber took her apart on Rod Laver Arena, Sharapova might have struggled with the German even at the height of her powers.

Kerber enjoyed an annus mirabilis in 2016, when she won the Australian Open, her first ever grand slam tournament, and the US Open, finishing runner-up at Wimbledon in between times. Only on the clay courts at Roland Garros in the French Open did she flounder, falling in the first round.

But 2017 was, in contrast, an annus horribilis for Kerber. She failed to make it past the fourth round in any of the grand slams she contested (her best efforts were in Melbourne and London) and by the end of the year the woman who had been ranked No.1 at the end of 2016 had fallen to 21st in the standings.

That is her seeding here at the Australian Open, but it was always likely to be an underestimation of her ability if she managed to get her game together.

Afterwards a delighted Kerber said that she was delighted to get the chance to perform at Rod Laver Arena where she had triumphed two years earlier.

"I have so many great memories, this court is very special for me," she said.

"I learned a lot from the last 24 months," she added, explaining how the ups and downs of the last two years had helped her mental strength.

A new coach - she ditched her previous mentor, Torben Beltz in favour of Belgian Wim Fissette - appears to have given her a new lease of life and she got off to a flying start in this clash, breaking Sharapova's serve in the first game.

The Russian briefly got back into the contest when she held (after a long struggle) in the third game of the first set to make the score 2-1, but that was as good as it got in the opening half hour.

Kerber controlled the tempo of the game, moving Sharapova around the court and hitting winners seemingly at will as she raced to a 5-1 lead, taking the first set by breaking Sharapova's serve.

The German began the second set in similar fashion and it looked as though this could be a very embarrassing evening for Sharapova as Kerber broke early once more and took a 2-0 lead.

But her opponent showed plenty of character to haul herself, however briefly, into contention by breaking the Kerber save and getting back on terms.

The pair traded games until the eighth, when Kerber broke again to give herself a 5-3 lead. Sharapova's resistance, game as it was, proved to be short lived, and when the end came it was quick, Kerber serving out to win comfortably.

Sharapova said that Kerber was " a lot more aggressive".

"I didn't return well in the first set. She is a confident player at the moment, and a lot of things were going well for her," Sharapova said.

She bemoaned the fact that she could not take advantage of the opportunity she had to get back into the game in the second set and said she still had work to do as there were "a lot of things I need to get better at".