De Minaur fights way into Shenzen quarters

Alex de Minaur has enhanced his reputation as Australian tennis' new battler, clawing his way into the Shenzen Open quarter-finals with a three-set win on Thursday.

Humbled in the first set and down 4-2 in the second, the 19 year-old came home with a head of steam to beat American Mackenzie McDonald 1-6 7-6 (7-1) 6-0.

He'll next meet Damir Dzumhur for a spot in the semi-finals, the match a likely preview of some Davis Cup action in February when Australia play Bosnia in a qualifying tie to make the main group of the new competition in November.

Bosnian fourth seed Dzumhur beat India's Ramkumar Ramanathan 6-4 6-2 in his earlier second round match.

De Minaur had demonstrated his fighting qualities in Washington last month, saving four consecutive match points in a second set tiebreaker against Andrey Rublev to progress to the tournament decider.

At the US Open he pushed 2014 champion Marin Cilic to five tight sets in a third-round encounter.