Australian teenager Thanasi Kokkinakis has succumbed to the brutal conditions in a cruel first-round US Open loss in New York.

Kokkinakis threatened to pull off a major upset before having to retire with severe cramping against 12th-seeded Frenchman Richard Gasquet.

The score was locked at two sets apiece – 4-6 6-1 4-6 6-3 – when the 19-year-old was forced to call it a day after dropping serve to trail 2-0 in the deciding set.

After seizing a two-sets-to-one lead, Kokkinakis dropped eight straight points after serving at 2-2 and 30-love in the fourth set.

He winced in pain as he was treated courtside and could barely move as the punishing heat and humidity took hold.

Kokkinakis rolled serves into play at less than 100kph before being reduced to under-arm serving at one point.

The South Australian looked to the heavens and despairingly told the tennis gods: “It’s absolute torture” before finally stopping after advice from the chair umpire to consider his health.

Shattered by his unfortunate demise, Kokkinakis smashed his racquet into the cement before staggering to the net to shake hands with Gasquet.

Kokkinakis’s sorry departure continues Australia’s disappointing start to the season’s final grand slam event.

Ajla Tomljanovic and qualifier John-Patrick Smith also joined the exodus on Tuesday.

Tomljanovic was unable to convert after taking the opening set in a 6-7 (1-7) 6-2 6-4 first-round loss to Italian Karin Knapp, while Smith also had opportunities in a 6-1 3-6 7-5 7-6 (7-4) defeat at the hands of experienced Russian Mikhail Youzhny.

The trio of losses follow first-round exits on Monday for Casey Dellacqua, Daria Gavrilova, John Millman and Matt Ebden, with Sam Groth Australia’s only winner so far.

Bernard Tomic and Lleyton Hewitt play later on Tuesday before Nick Kyrgios takes on third seed Andy Murray in the feature night match.