There's clearly something about the Pat Rafter Arena that brings out the most nuggety parts of Jordan Thompson's fighting spirit.

And just as in 2024 when he kicked off his best-ever year at the Brisbane venue, 'Thommo' has begun his latest campaign there with the sort of familiar backs-to-the-wall resilience that suggests 2025 could prove even more fruitful for this most admirable late bloomer of Australian tennis.

"I guess I don't know what the words 'give up' mean," shrugged Thompson, summing up his best quality after he'd saved three first-set points from a fairly desperate position to then go on and outplay young American riser Alex Michelsen 7-5 6-3 in Wednesday's late match.

It's set up the 30-year-old with a quarter-final spot at the Brisbane International for a second-straight year, and rekindled a few memories of last year's event which proved the perfect launchpad for him to enjoy a career-changing year that featured his first tournament singles triumph and a rise to a new ranking-high of 26.

"It all started here last year. I beat Rafa (Nadal) in a three-hour marathon and it really kick-started my year and gave me a lot of confidence and belief. Sort of just went from strength to strength in singles and doubles," reflected Thompson.

Now he's got the chance to measure how far he's travelled over a year in which he not only jumped 29 places in the rankings but also won his first grand slam doubles at the US Open.

Because on Friday, he'll meet reigning champ Grigor Dimitrov, who knocked him out of the Brisbane International last year, in the quarter-finals.

"He's the one who took me down here last year in the semis. So, defending champ, he's in great form, back in the top 10, it's going to be another test," said Thompson, who's already knocked out former Wimbledon finalist Matteo Berrettini from a set down this week.

Michelsen, the 20-year-old American who's soared to No.41 in the world, suffered a nosebleed in the second game against Thompson but it didn't stop him dominating the early stages, racing into a 2-5, 0-40 lead in the opening set before the eighth-seeded Sydneysider battled back

"I snuck out the set and actually got a little bit worried there when I had a few match points, and he started coming back," Thompson noted after Michelsen delayed his defeat by saving three match points when serving at 3-5 down.

"Thankfully I got it done in that game."

Like Thompson, though, Dimitrov is ageing like a fine wine. At 33 and ranked 10 in the world, the 2017 Australian Open semi-finalist is playing some lovely stuff, having beaten another in-form Sydneysider Aleksandar Vukic 6-2 7-6 (7-5) on Wednesday.

Novak Djokovic will top the bill on Thursday evening against ever flamboyant Frenchman Gael Monfils, who could be forgiven for sighing deeply at the thought of having to play the great man who leads their 20-year-old head-to-head score by the ouch-worthy margin of 19-0.