A surly Sharapova was in no mood to answer questions about her controversial seven-minute toilet break between the second and third sets of her 4-6 6-1 6-4 fourth-round loss to Barty on Sunday.

But the Russian was happy to laud her fourth-round vanquisher as a potential winner of the trophy after Barty added the former world No.1 and five-time grand slam champion to her growing list of big-name summer scalps.

"Everyone has a chance and everyone has an opportunity," Sharapova said when asked if she felt the 22-year-old was ready to breakthrough for her maiden major at Melbourne Park.

"(It's) whether you take it.

"I thought she played some brilliant tennis in parts of the match, and you have to deliver that for three more.

"So time will tell."

Undermined by 10 double-faults in a serving horror show, Sharapova paid tribute to Barty's unique style rather than cursing her own performance.

But the 2008 Open champion did lament not converting either of two break-point chances deep in the third set and getting the match back on level terms.

"A really tough style to play against. I thought she played a really great match," said Sharapova, who had ended Caroline Wozniacki's title defence in her previous match on Thursday.

"I still had my chances which I didn't take. I definitely had a letdown for many games straight, gave her that confidence, and she's a confidence player as well.

"She'll take it. She's not going to back down."

The icy Russian was jeered by the Rod Laver Arena crown after leaving Barty waiting in what appeared to be an act of gamesmanship to try to halt the Australian's momentum.

But she refused to answer whether or not the booing rattled her.

Sharapova also took exception to a question about her no longer being able to take meldonium, a drug she used for a decade before being suspended for 15 months after continuing to use it it was banned.

"Now that it's banned and you can no longer take it, is that a struggle physically to deal with it, the demand of a grand slam fortnight?" she was asked.

"Is there another question?' Sharapova fired back.

Sharapova's defeat, as well as the shock exit on Sunday of second seed and fellow former champion Angelique Kerber, has blown Barty's bottom half of the draw wide open.

If Barty can topple Czech sixth seed and two-time Wimbledon champion Petra Kvitova in Tuesday's quarter-finals, the Queenslander will face either Kerber's surprise conqueror Danielle Collins, unseeded Russian Anastasia Pavlyuchenkova or world No.5 Sloane Stephens for a place in the title decider.

Australian Associated Press