* Matt Trollope is a journalist for Tennis Australia, which has contributed this piece

Patience, resilience and dedication have combined to reward Thanasi Kokkinakis, who scored the biggest win of his Grand Slam career, over Stefanos Tsitsipas at the US Open on Wednesday (AEST).

Buoyed by a vocal crowd on the Grandstand court, the 86th-ranked Australian maintained his composure and aggressive mindset in a near four hour battle, upsetting the world No.11 7-6, 4-6, 6-3, 7-5 to reach the second round in New York for the first time in five years.

After years of injury struggles, and the anguish that accompanied them, Kokkinakis, now 28, is finally seeing the results of his persistence and tenacity.

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For just the third time in his career, he has now contested the main draw of all four Grand Slam tournaments in one season.

And for the first time, he won his opening round match at all four.

He has scored just three wins over top-20 players at Grand Slams throughout his career, the first of those coming almost a decade ago against Ernests Gulbis at the 2015 Australian Open.

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But his most recent two have come at the past two majors – first after saving match points to beat world No.17 Felix Auger-Aliassime at Wimbledon, and now over Tsitsipas, who has been a top-10 player for the bulk of the past five years.

“I’ve had a couple – a lot – of tight losses when I’ve been in winning positions, so that one’s just all relief,” said Kokkinakis, who fell to Tsitsipas in five sets in the second round of the 2021 AO.

“I missed a lot of my career through the middle period, so I’m just trying to make up for whatever I have left, and just keep hustling and see how we go.

“I have the ultimate belief in my game. I felt like my body was holding me back for a long period of time.

“But everyone’s so good here. Stacked top to bottom, honestly, No.1 player in the world to 200, everyone’s a really good player, and if you’re not bringing your best you can lose on any given day.

“So not taking it for granted, just trying to go as well as I can and put as much effort into this sport as I have. I’ve maybe taken it for granted a little bit in the past when I was a bit younger, so just giving it a go.”

Addressing the crowd, Kokkinakis added: “This is why you play – to play in front of you guys on big stadiums in massive cities. So yeah, incredible feeling.”

Indeed, when Kokkinakis was younger, things came easier.

Blessed with power, athleticism and prodigious talent, he was a junior finalist at both the Australian and US Opens in 2013, and quickly transitioned to the pro ranks.

He won his first Grand Slam main draw match at age 17 at the 2014 AO, and 12 months later upstaged Gulbis at the same venue.

At Roland-Garros in 2015, he went on to reach the third round, and peaked at world No.69 following that result.

Yet 2015 would be the last time in seven years the popular South Australian played all four Grand Slam main draws in the same year.

Injuries mounted, and persisted.

“There’s obviously that middle period in between in my career, for five or six years,” he recalled, “where I was just pretty much a no show, trying to get back and couldn’t.”

Yet since 2022, which began with his first career ATP title in Adelaide, Kokkinakis has been a more regular fixture on tour.

He has learned a lot about his body, and what he requires to compete at the highest level.

He made the decision earlier this month to forgo tournaments after Montreal and instead committed to a training block in Bradenton, Florida.

“If anyone’s been there, you know there’s not a whole lot to do but train. So that was what my goal was, to kind of set myself up for moments and matches like this, and super happy it paid off,” Kokkinakis explained.

“But my best win at a Grand Slam, for sure – just a lot of hard work’s gone into it, staying positive and just competing my nuts off, really.

“It’s been well documented I’ve had some tight ones, but I’m starting to get on the winning end of them now.”

More than eight years after he first set it, Kokkinakis finally improved on his career best ranking in October 2023, and has since risen as high as No.65.

In the past two seasons he has returned to the third round at Roland-Garros, and will be looking to do the same at the US Open when he next takes on Nuno Borges.

It’s a segment of the draw that has opened up, given Kokkinakis eliminated Tsitsipas and Auger-Aliassime – the other seed placed there – also suffered a shock first round loss to Jakub Mensik.

The four players remaining in that part of the draw – Kokkinakis, Borges, Mensik and another Aussie in Tristan Schoolkate – are all unseeded, and one of them will go on to reach the fourth round.

It’s a stage Kokkinakis has yet to reach at a Grand Slam tournament, and he’d love to do it in New York.

“I’ve never felt like I’ve played my best tennis here, which is surprising, because it should suit me and my game,” said Kokkinakis, who has passed the first round just twice in six main draw appearances at Flushing Meadows.

“But I’ve just been training well, and I was able to play somewhat close to the level in training, so that was important.”