Winnetka, United States, 12 July 2019 |

Thanasi Kokkinakis has won back-to-back matches for the first time since Australian Open qualifying to reach the quarterfinals of the ATP Challenger tournament in Winnetka, Illinois.

The injury-plagued South Australian advanced to the last eight of the hard-court tournament when Argentine Guido Andreozzi retired when trailing 7-6(5) 4-0 due to a leg injury.

A round earlier, Kokkinakis beat Colombia’s Alejandro Gonzalez 6-4 6-3 in what was his first match win since April.

That came at the clay-court Challenger in Barletta, Italy, where Kokkinakis won his opening match before being forced to withdraw from the event due to a right pectoral injury.

It was the same ailment which saw the Aussie retire in the second set of his first-round Australian Open match against Taro Daniel, after winning three rounds of qualifying.

Winnetka marks just the fourth tournament Kokkinakis has contested in 2019; in addition to Barletta and the Australian Open, the former world No.69 played in Brisbane, where he qualified for the main draw before losing in the first round to Jo-Wilfried Tsonga.

He will face either Jason Jung or Michail Pervolarakis for a place in the Winnetka semifinals.

Another Australian, Jason Kubler, is also into the last 16, and takes on Stefan Kozlov.