Shunning the supposed pressure of being top seed at a grand slam for the first time, Barty led Australia's batch of big guns into the second round of Wimbledon with a nerveless display on day two of the championships.

Alex de Minaur, Nick Kyrgios and US Open quarter-finalist John Millman also safely progressed to give Australia six first-round winners in total.

But it was the new queen of women's tennis who impressed most, Barty sweeping past Zheng Saisai 6-4 6-2 to extend her winning streak to 13 matches.

A day after a teary Naomi Osaka crashed out and claimed she'd prefer not to be No.1 and carry all the pressure, Barty needed only 76 minutes to advance.

"Came into it thinking kind of like Hakuna Matata; just relax and go for it. Really nice to come in here, get stuck into that first match," Barty said.

Barty is the seventh different women's world No.1 since Williams last held top spot before taking maternity leave after her winning her 23th grand slam crown while pregnant at the 2017 Australian Open.

But while Osaka was crippled with anxiety by her lofty status, Barty said she was "loving every minute of it".

"For me (being No.1), it's a little bit irrelevant," she said.

"The only pressure I have is what I put on myself, making sure I'm doing all the right things, preparing in the right way.

"Just play each match as it comes. There's certainly no extra stresses on any match.

"As for Naomi, I can't really comment on what she says. We've had an incredible year. To be where we are is really exciting. Loving every minute."

A 24th major for Williams, who lost last year's final to Angelique Kerber, would draw the 37-year-old level with Barty's legendary compatriot Margaret Court on the all-time grand slam singles leaderboard.

If it was Barty who stopped the American in 2019 and then went on to raise the Venus Rosewater Dish on Saturday week, the 23-year-old Queenslander would need to join Williams as only the second woman since the turn of the century to complete the French Open-Wimbledon double.

"Shows just how exceptionally hard it is," Barty said of the transition from clay to grass.

"For me, it's a possibility, but it's certainly not something we're thinking about.

"It's about going match by match, trying to do the best that I can in every single tennis match that we play here.

"If we can give ourselves the opportunity, that would be great."

Barty's more immediate task is beating Belgium's world No.58 Alison Van Uytvanck on Thursday.

De Minaur also marched into the second round without dropping a set, the 25th seed casting aside 2018 French Open semi-finalist Marco Cecchinato 6-0 6-4 7-6 (7-5).

Kyrgios set up a Centre Court blockbuster with Rafael Nadal after denying his former junior doubles partner Jordan Thompson 7-6 (7-4) 3-6 7-6 (12-10) 0-6 6-1 in an epic all-Australian first-round encounter.

Millman hammered Bolivian Hugo Dellien 6-2 6-3 6-4.

But Bernard Tomic, Matt Eben, Samantha Stosur and Arina Rodionova all followed Thompson out the exit gates.

AAP