Ashleigh Barty has survived an injury scare and a spirited challenge from Maria Sakkari to scrap her way into the Australian Open fourth round for the first time.

Australia’s big title hope needed a medical time-out after the first set to treat an apparent abdominal strain but returned to complete a hard-fought 7-5 6-1 third-round win over the tough Greek.

The victory earned the 15th seed a last-16 crack at titleholder Caroline Wozniacki or fellow former champion Maria Sharapova on Sunday.