Carey is understated and unselfish, and his team-mates love him for it

There was a telling moment when Alex Carey brought up his first Test century.

While Carey had his head down, sprinting for the first of three runs after square-driving Marco Jansen, his batting partner Cameron Green had both his arms aloft in celebration. Carey's own celebration was fairly understated, especially when compared to David Warner's on day two. But Carey had much to be proud of. He was the first Australian wicketkeeper to score a Test century since 2013 and just the seventh overall.

But showmanship and self-adulation are not in Carey's DNA as a cricketer. He is more likely to boast about his highlights as a one-time professional Australian Rules footballer. Understated is who he is as a cricketer. He has become the drummer in Australia's band and an incredibly reliable and much-loved one at that.

There were concerns about how Australia would replace Tim Paine ahead of last year's Ashes. There was even an undercurrent throughout Australian cricket querying whether Carey was the right choice despite being the long-time understudy, given the raw talent of Josh Inglis or the consistency of Jimmy Peirson. And that undercurrent has remained even after a year in the job.

But it will have disappeared now after a classy century that has all but put the MCG Test in Australia's safekeeping. In reference to replacing Paine specifically, for the quality of Paine's glovework and his performance as leader in a difficult period, Carey always represented a significant upgrade as a batter both in his record at first-class level and his skillset.

Carey's first Test century showcased all those skills. His elegance, power, and wide array of strokes were all on display.

Carey unfazed as wickets fall around him

Admittedly, he had the benefit of feasting on a weary South African attack. He had walked out at 363 for 3 in the 85th over at the end of a 37-degree day with Australia leading by 176. But there was a point early on day three where Australia's innings might have fallen in a heap. Anrich Nortje ripped through Travis Head and David Warner in consecutive balls and then Kagiso Rabada had Pat Cummins caught behind four balls later. Carey was just 16 not out as he watched it all unfold, with Australia 213 in front.

But Carey was unperturbed and unfurled one of the shots of the match. It was a part-Gilchrist, part-Lara flashing square drive with anchored feet, off a Nortje rocket at that. From there he produced the full array. There were uppercuts over third, controlled check-drives down the ground, reverse-sweeps and sweeps off Keshav Maharaj, and pulls and cuts galore.

He formed a superb partnership with Green, who fought bravely with a fractured finger to post an unbeaten half-century and share a 117-run stand with Carey to demoralise South Africa.

"I actually didn't think he was going to walk out the race today," Carey said of Green after play. "But to see him put on a brave face, bat beautifully and allow me at the other end to bat as well... allowed us to put on a really good partnership."

The two complement one another beautifully and it shows. In ten innings together at Test level, they have combined for 511 runs at 51.10 per stand with two century partnerships. It is the perfect blend of yin and yang. A shorter left-hand batter and a tall right-hand batter make them a difficult duo to bowl at. But their personalities and game styles blend very well. Green is a worrier, constantly asking questions of his partner about what the bowlers and the pitch are doing. Carey is the complete opposite, keeping things simple and keeping Green calm. But Green's attention to detail keeps Carey locked in. Carey's busyness and intent to rotate and score brings Green out of his shell. The quality and stubbornness of Green's defence at times reminds Carey to find the right Test-match tempo to his batting and that he doesn't need to score off every ball.

"I think we ebb and flow at times really well," Carey said. "Today it was probably on me to score a bit (and) more on him to grit through and he did that amazingly. I don't really know how to explain it. I think just with certain guys, you just have that calmness and confidence. It's been fun so far, and hopefully a few more big partnerships and no doubt he'll get his ton."

They produced match-winning stands in Lahore and Galle earlier this year and this, too, while not the defining partnership of the match, is still likely to result in an Australia win.

Carey remains team-first, and the team loves him for it

It is those shared partnerships that led to Green's spontaneous celebration for his mate's milestone. But also, there is a recognition of how unselfish Carey has been as a Test batter. People have been quick to point to his average at times as a measure of why Carey's place as Australia's wicketkeeper should not be assumed, particularly as there have been critics of his glovework.

But Carey's unselfishness with the bat has not gone unnoticed within the team, even if it has elsewhere. Four times in his first 12 months of Test cricket, he has sacrificed his wicket cheaply trying to advance the game for his team. If you remove those innings from his record, he would average over 40.

And his glovework remains his number-one priority. Prior to day three at the MCG, even though he was not out with the bat overnight, he spent the first part of his warm-up doing specific keeping work catching spin in the nets in preparation to keep long periods to Nathan Lyon in the second innings.

Carey later took an excellent catch down the legside off Cummins to remove Dean Elgar. But his century now gives Australia options given they are set to lose Green at No. 6 for the Sydney Test.

Three of Carey's first-class centuries have come batting in the top six as has his lone ODI century. He has a first-class century batting at No. 5 for South Australia against a New South Wales attack featuring Mitchell Starc, Josh Hazlewood and Lyon. Australia haven't had a wicketkeeper picked specifically to bat at No. 6 since Matthew Wade nearly a decade ago.

"Whatever opportunity I get for the Australian cricket team I'll put my hand up to do," Carey said.

He remains team-first at all times, and his team is grateful for that.