The 15-year-old, who made a memorable run to the Wimbledon last 16 in July, reached the Linz Open last eight when opponent Kateryna Kozlova retired.

Gauff has provisionally climbed to 94th in the rankings, closer to automatic qualification for the Australian Open.

She lost in Linz qualifying but entered the main draw as a lucky loser.

Following Greek Maria Sakkari's withdrawal, Gauff beat Swiss Stefanie Vogele on Tuesday and progressed again when Ukrainian Kozlova quit while trailing 6-4 4-6 0-2.

Gauff, who does not turn 16 until March, is the youngest player to reach a WTA quarter-final since Bulgarian Sesil Karatantcheva in January 2005.

The Austrian tournament is Gauff's first appearance since suffering a comprehensive defeat, which left her in tears, by Naomi Osaka at the US Open last month.

Gauff became the youngest player in the Open era to reach the Wimbledon main draw and was given a wildcard to play at her home Grand Slam in New York.

Although most would expect her to receive a wildcard for the Australian Open, she is on course to qualify automatically with the top 100-ranked players going straight into the main draw in Melbourne.