“She’s playing unbelievable, and she’s had such an amazing year last year and this year as well,” Williams told AAP.

“She’s continuing her amazing rise since she came back and been so focused on tennis.

“She does everything great.

I’ll be excited to go out and see what I can do,” she said.

The last time the two met was in the first round of the 2014 Australian Open when Barty was just 17-years-old and prior to her 18-month break from tennis. 

Barty returned to the sport and has since established herself in the world’s top 20 but the now 22-year-old says it has been hard to ignore the hype surrounding the match.

“As soon as I got off the court, I’m walking past and it’s on the big screen," she told AAP.

"It’s a bit hard to avoid."

Williams was overlooked for a seeding at Roland Garros after having her first child, Alexis Olympia Ohanian Jr. in September 2017. 

In her attempt to return to tennis, she has had setbacks including missing the 2018 Australian Open after suffering another pulmonary embolism and slipped to No.451 in the world.

In the first round, Williams win in straight sets 7-6(4) 6-4 over Czech Kristyna Pliskova.