US Open finalist Madison Keys has sent a message that her 2017 season-end form was no fluke, running roughshod over Romanian Ana Bogdan at the Australian Open.

The 20-year-old Keys, the highest-seeded American remaining in the women’s draw, didn’t drop a single service game against the 102-ranked Bogdan in the 6-3 6-4 victory on Saturday.

Returning to Melbourne Park after wrist surgery sidelined her from last year’s Open, the 17th seed blasted her way into the fourth round with 29 winners and six aces on Margaret Court Arena.

Yet to drop a set through her first three matches, Keys’s big-hitting from the back of the court wore down the inexperienced Bogdan – playing in her maiden grand slam third round.

“I definitely felt that way,” said Keys, who made a run to the Open semi-finals as a teenager in 2015.

“But she was also getting to a lot of balls and definitely made me play my best tennis.”

After enduring a first set arm wrestle, Keys converted a fourth-break point chance at 4-3 to go ahead.

Despite serving at 46 per cent on first serves, Keys never gave the Romanian a sniff taking the opening set without facing a break point.

Keys converted her first match point to put the Romanian away after one hour and 13 minutes.

Keys, who has spent a tick over three hours on court this week, will meet either French eighth seed Caroline Garcia or Belarusian Aliaksandra Sasnovich for a quarter-final spot.