'So much to play for': Joe Root's ton was about more than the personal milestone - but was it his last in Australia?

SCG: Joe Root may not know what demonstrative means but his acknowledgement of the SCG crowd was exactly that after his 41st Test century.

At 35, the very real reality for the Australian public is that could be one of the last sightings of one of the greatest players to ever grace the international arena.

Root's hundred put him equal with Ricky Ponting for Test centuries and he now sits behind only Jacques Kallis and Sachin Tendulkar.

READ MORE: Ashes gets 'heated' after expletive-laden Stokes spray

READ MORE: Aussie digs deep to claim three-set thriller in Brisbane opener

READ MORE: Rodgers extends career after wildest end to NFL season

The knock for those who wish to criticise Root before this series was the fact he hadn't scored a century in Australia.

Now he has two.

Those critics, they've been kicked to the kerb.

Root has reached his Everest and doesn't owe England anything, but no doubt there'd be a fire inside him to win an Ashes series in Australia.

With Australia's side set to undergo generational change, who knows what it will look like in four years - although Root will likely be here for the anniversary Test next year.

Root's determination for that elusive win was clear in Brisbane after his first ton here.

At the press conference after his breakthrough milestone at the Gabba, there was a sternness and steel about the mild-mannered Root. He wanted it to be a match-winning century, but evidently it wasn't and the Ashes was lost by the next match.

There's no doubt at the SCG it's the same.

"One thing I always look at is opportunity, and I don't know how many opportunities I'm going to get to come back to Australia," he said after play on day two.

"Obviously last week was great to win at the MCG and I guess that presented another opportunity here this week to try and help us get in a position of strength in this game early on, to try and replicate that feeling last week for the group and hopefully that benefits the Test team moving forward when they come back here.

"A lot of this squad, it's the first time they've been out here ... if we can find a way to win this fixture, next time we come out here the memories we will be two Ashes wins and the baggage that might have been there for a previous generation might not be there for them. There's so much to play for in the next three days."

With Root talking about future generations, the focus will move to whether can be part of that next series in the 2029 summer.

At this stage, there is no one coming for his spot and nor should there be. The 35-year-old has been England's best across the tour.

When Root drove Michael Neser down the ground to bring up his century, there was an immediate fist pump. Root took the helmet off and raised his bat like usual before offering the same shrug he did at the Gabba.

When he was dismissed, Root then managed to acknowledge the whole crowd.

It was put to Root at the SCG on day two that his celebration was "quite demonstrative".

At first he had to clarify what that meant. Then he shut down any lingering speculation.

"I think you might be looking into it too much," he said.

"We've had some amazing support throughout this series. We've not been able to achieve what we set out as a group but at no point has that ever wavered.

"Whenever I've come out here on tour it's been exceptional and it's a way of saying thank you."

Root then pushed straight towards the elephant in the room and suggested the question was leaning towards whether he'd be here in four years.

Laughter came from the press conference, because everyone knew it was.

Root's answer was "who knows?"

"We'll see, I'd love to (come back) but we'll see how things unfold in time."