Patty Mills, left, with Spurs coach Gregg Popovich and Manu Ginobili.

Patty Mills, left, with Spurs coach Gregg Popovich and Manu Ginobili. Photo: Getty Images

Canberra basketball star Patrick Mills has turned a blast from his coach into inspiration for career-best form, declaring he wanted to prove a point to his NBA doubters after Gregg Popovich labelled him "a little fat-arse" with "too much junk in the trunk".

Mills and the San Antonio Spurs will begin their bid for NBA finals redemption on Friday morning (Australian time) when they play game one against the star-laden Miami Heat.

Mills is set to cash in on the best year of his NBA career when he signs his next contract at the end of the championship series, with the Australian Boomers point guard's price tag set to rise after a breakout season.

A year ago, Mills' contribution was limited to choreographed towel waving and cheering from the Spurs' bench.

But after Popovich delivered some harsh truths, he has been on a mission to earn respect in the world's best league.

Mills hired a personal chef and gave up some of his food loves – strawberry milk, cheese, pasta and Vegemite – in a bid to chase more NBA game time.

Now he is a key cog in the Spurs' championship ambitions, as they aim to end the LeBron James-led Heat's quest for a title three-peat.

"To be honest, [the little fat-arse comment] is nothing, I've heard a lot worse from him," Mills said.

"I wanted to come in this year and make this impression and make a statement this season. I think I've done that."

Mills is set to be thrust into a bigger-than-expected role in the finals as star guard Tony Parker battles ongoing injuries.

He says he is ready. "I think Tony is going to be fine, but everyone, including me, is ready to step up. All the work I did in the off-season was to be able to contribute now.

"We definitely believe in ourselves that we can go and get it done, but we know it will be tough."

The former Marist College student is aiming to become the first indigenous Australian to win an NBA title. He has put contract negotiations on hold until the end of the seven-game series to ensure there are no distractions.

In his fifth season in the NBA, Mills is averaging 10.3 points per game and has cemented his place as Parker's back-up.

Mills scored 838 points in his first four seasons in the NBA, but has scored 943 points this season alone – including 117 points in the play-offs.

Mills was injured when the Spurs lost game six and seven of last year's championship series to the Heat, and the 25-year-old says San Antonio is determined to get rid of the "bitter taste".

"I was overwhelmed last year; the NBA finals are huge and last year was my first time," Mills said. "I worked so hard in the off-season because I wanted to be a part of this, I want to make a contribution and I'm really excited for that.

"I know what to expect now, I know what's coming and how big a deal it is. We want a crack at Miami again and it's been burning all year.

"I made a lot of strides this year as a player with what I've learnt. I find myself believing in myself even more ... the more I believe in myself, the better I can be."

Mills' transformation has impressed Popovich so much that the veteran coach rates him as one of the most crucial cogs in the Spurs' success.

"He came in [this year] scoped, cut, whatever you want to call it," Popovich said. "Faster and stronger, we talked about getting his game in the head a bit more. We know he's a great shooter but we want him to get everybody else involved this year.

"He's probably the most significant factor for us coming off the bench besides Manu [Ginobili]."