Australian tennis battler Chris O’Connell has continued his extraordinary rise to prominence with a fighting four-set first-round win at the US Open.

O’Connell beat Serbian Laslo Djere 4-6 6-4 7-6 (7-2) 6-4 on Wednesday for his maiden victory at a grand-slam event.

The 26-year-old’s reward, apart from a $A136,000 pay day, is a possible shot at Russian third seed and 2019 runner-up Daniil Medvedev on Friday for a place in the last 32.

O’Connell soared from outside the world’s top 1000 to the cusp of the top 100 after reaching 14 finals on the ITF Futures and Challenger tours last year, collecting five titles.

After a career dogged by injury, he had been cleaning boats on Sydney’s Pittwater Harbour to make ends meet before chalking up an unrivalled 82 match wins for the 2019 season.

As a wildcard, O’Connell showcased his grand-slam potential at the Australian Open in January, where he pushed world No.15 Andrey Rublev to four sets.

Not even the five-month suspension of the world tennis tours due to COVID-19 has been able to stall his momentum.

Ranked 35 spots below Djere, O’Connell dropped the opening set on his Open debut before mounting a spirited comeback.

The world No.116 trailed by a service break in the third set but, undeterred, eventually wore down the Serb to prevail in a three-hour, nine-minute physical battle on Court 8.

The life-changing victory has already doubled O’Connell’s 2020 on-court earnings.