Australian tennis prodigy Alexei Popyrin has overcome a horror start to match his career-best grand slam run with a stirring second-round US Open win in New York.

The just-turned 20-year-old former grand slam junior champion fought back from a set and a break down to defeat Mikhail Kukushkin 2-6 7-5 6-3 6-2 and set up a date with big-hitting Italian Matteo Berrettini.

Berrettini, the 24th seed, earlier on Thursday ended Jordan Thompson’s campaign with a 7-5 7-6 (7-5) 4-6 6-1 win over the Australian No.3.

Popyrin, who ousted world No.4 Dominic Thiem en route to the last 32 of the Australian Open and also won matches at the French Open and Wimbledon, is enjoying a stunning first full season at the slams.

His latest victory, after dropping the first four games and then falling behind 4-2 in the second set, will send the 2017 Roland Garros junior champion from outside No.105 in the world to inside the top 90 – with a bullet.

Another win at Flushing Meadows and Popyrin will be headed for uncharted waters – the last 16 of a major and a possible all-Australian showdown with Nick Kyrgios, who plays French qualifier Antoine Hoang later on Thursday.

Popyrin struck 44 winners to Kukushkin’s 23, including 15 aces, and broke the Kazakh seven times during the two-hour, 35-minute match-up.