Barty, seeded 15, saw off the unseeded Sakkari 7-5, 6-1 in 82 minutes to reach the last 16, her best performance at Melbourne Park after third round appearances in 2018 and 2017.
 

She is yet to drop a set and finished in time to see the start of Australia's third one-day international against India at the neighbouring Melbourne Cricket Ground.
 "Ice bath, physio, coffee, cricket -- I'm good," she said when asked about her post-match plans.
 The 22-year-old will face a fourth-round test against the victor of the blockbuster clash between defending champion Caroline Wozniacki and five-time major winner Maria Sharapova later Friday.
 Barty is currently among the standout players on the women's tour, winning seven of eight matches this month to back up a title victory in Zhuhai late last year.
 With intermittent rain at Melbourne Park, she needed to adjust to playing under the closed roof on centre court but rolled past Sakkari after familiarising herself with the conditions. 
 "It took some time to get used to how dead and slow it is in here with the roof closed, but there was never going to be much in it," she said.
 "Maria's a great friend of mine, we've had some exceptional matches in the past. So I'm happy to come through in straight set and find my way towards the end there."
 Barty had a medical time out after the first set but said the problem, which she did not disclose, was not a threat to her Open campaign.No Australian woman has won the season-opening Grand Slam at Melbourne Park since Christine O'Neill in 1978.