Alex de Minaur is promising to continue fighting through the pain barrier after crowning another red-letter day for Australia's tennis stars at the US Open in New York.
Playing his first match in seven weeks, a hurting and underdone de Minaur dug deep to be one of 10 Australians into the second round with a 6-3 6-4 5-7 6-4 victory over American Marcos Giron.
Thanasi Kokkinakis, Jordan Thompson and inspired wildcard Tristan Schoolkate also scored rousing wins, before Max Purcell and Chris O'Connell continued Australia's magnificent start to the final grand slam of the year.
"Australian tennis is thriving," de Minaur saluted after revealing the full extent of the despair and frustration he'd endured since pulling out of his Wimbledon quarter-final blockbuster with Novak Djokovic.
The world No.10 said a series of different diagnoses had left him in limbo.
"Mentally it's tough when you get told a certain thing, and then all of a sudden it goes from three to eight weeks (of being out)," de Minaur said.
"Then, at one stage, I got told it would look like the season ending in surgery, so there was a lot of different opinions and plans being thrown out."
De Minaur's next test will come against Finnish qualifier Otto Virtanen on Thursday (Friday AEST).
Fan favourite Kokkinakis roared with emotion and received a standing ovation on The Grandstand after upsetting dual grand slam runner-up Stefanos Tsitsipas 7-6 (7-5) 4-6 6-3 7-5 for the biggest grand slam win of his stop-start career.
Incredibly, the fighting four-set triumph over the 11th seed was only Kokkinakis's second victory at the Open in nine injury-plagued years.
"Super happy, super pumped," the 28-year-old said.
Kokkinakis's reward is a golden opportunity to finally make a grand slam run in a wide-open pocket of the draw.
He next faces unseeded Nuno Borges, with Schoolkate a potential round-three opponent following the West Australian's own watershed win over Taro Daniel.
Schoolkate vindicated his wildcard entry with a steely 4-6 4-6 6-4 7-6 (8-6) 6-4 comeback victory on his long-awaited grand slam main-draw debut.
"It's fantastic. I'm obviously very happy to get through that match," said the world No.193.
The 23-year-old Schoolkate earned a second-round shot at Czeck Jakub Mensik, not to mention a life-changing career pay day of at least $US140,000 ($A207,000).
Thompson shook off the disappointment of missing a seeding by one lousy rankings spot to blow away Constant Lestienne 6-1 6-3 6-2 in less than two hours.
The world No.32 did his best to escape the searing heat by breaking the Frenchman six times without dropping his own serve once.
Thompson will play world No.7 Hubert Hurkacz for a place in the last 32.
Max Purcell progressed with a bittersweet 7-5 6-4 6-3 win over fellow Sydneysider Aleksandar Vukic, while O'Connell upset Chilean 26th seed Nicolas Jarry 6-4 6-4 4-6 6-3 to join the party.
Late-blooming qualifier Li Tu lived up to his word, producing some of the tennis of his life in the feature night match on Arthur Ashe Stadium against Spanish whiz Carlos Alcaraz.
But the 28-year-old had to settle for best support act in a pulsating 6-2 4-6 6-3 6-1 loss to the French Open and Wimbledon titleholder and four-time grand slam champion.
First-day winners Alexei Popyrin, Rinky Hijikata, Ajla Tomljanovic and 18-year-old qualifier Maya Joint will be out to continue the Aussie revolution on Wednesday (Thursday AEST).
But women's wildcard Taylah Preston's international grand slam debut lasted just 61 minutes in a 6-2 6-0 first-round loss to Russian seed Anastasia Pavlyuchenkova.
Daria Saville's comeback from a foot injury finished in utter frustration, the Australian No.1 losing 6-3 4-6 7-6 (10-6) to Japanese qualifier Ena Shibahara in a three-hour, 16-minute cliffhanger.
Destanee Aiava's run from qualifying ended with a gallant 6-1 7-6 (7-1) loss to fourth seed Elena Rybakina after the underdog had three set points in the second set.
James Duckworth and Arina Rodionova also suffered gallant first-round defeats.
HOW THE AUSSIES FARED ON DAY TWO OF THE US OPEN AT FLUSHING MEADOWS
Men's singles, first round
10-Alex de Minaur bt Marcos Giron (USA) 6-3 6-4 5-7 6-4
Jordan Thompson bt Constant Lestienne (FRA) 6-1 6-3 6-2
Thanasi Kokkinakis bt 11-Stefanos Tsitsipas (GRE) 7-6 (7-5) 4-6 6-3 7-5
Max Purcell bt Aleksandar Vukic 7-5 6-4 6-3
Chris O'Connell bt 26-Nicolas Jarry (CHI) 6-4 6-4 4-6 6-3
Tristan Schoolkate bt Taro Daniel (JPN) 4-6 4-6 6-4 7-6 (8-6) 6-4
Li Tu lost to 3-Carlos Alcaraz (ESP) 6-2 4-6 6-3 6-1
James Duckworth lost to 31-Flavio Cobolli (ITA) 6-1 4-6 6-4 6-4
Women's singles, first round
Arina Rodionova lost to Xinyu Wang (CHN) 3-6 6-4 6-1
Taylah Preston lost to 25-Anastasia Pavlyuchenkova (RUS) 6-2 6-0
Daria Saville lost to Ena Shibahara (JPN) 6-3 4-6 7-6 (10-6)
Destanee Aiava lost to 4-Elena Rybakina (KAZ) 6-1 7-6 (7-1)
