What it's like to play world number one Ash Barty at the Australian Open

When words such as «tough», frustrating" and «tricky» are used to describe Ash Barty as an opponent, it is easy to see why the Australian sits atop the world rankings. 

Barty already has two majors in her keeping — the 2019 French Open championship and last year's Wimbledon title — and she remains favourite to add another to her tally at Melbourne Park.

Her Australian Open campaign has so far been impressive. The 25-year-old is yet to drop a set and her serve has only been broken once.

And perhaps posing as an ominous warning for her US rival Madison Keys in tonight's semifinal on Rod Laver Arena, Barty's coach Craig Tyzzer feels his charge can still improve on her performances at the tournament.

Ash Barty's coach believes his charge can take her game to another level at Melbourne Park.

Keys — a former world number seven and US Open finalist — will not be a pushover, as Barty and her «team» have acknowledged.

She has been in superb form in Melbourne, as illustrated by her convincing victories over seeds Barbora Krejčíková and Paula Badosa in her two most recent matches.

But while Keys is immensely talented, she will have to come up with a strategy to outwit Barty, whose game appears to have so few weaknesses.

«You feel pretty helpless,» said Jessica Pegula, after she lost to Barty in the quarterfinals.

«I think that when she gets into a rhythm … her game just kind of picks you apart a little bit, and it can be really frustrating because you don't feel like you can get a lot of free points, there's really not much you can do.

»I think with her you have to take your chances when you can, and when you don't, she definitely tends to run away with the match a little bit.

«It doesn't feel good. It feels kind of helpless. I didn't feel