England are confident the building blocks of an Ashes-winning team are "falling into place" after celebrating an emphatic 3-1 series win in South Africa's backyard.
The tourists followed the day-five drama in Cape Town and the innings victory in Port Elizabeth with one more big push at the Wanderers in Johannesburg, putting the seal on a 191-run success by bowling out the hosts midway through the fourth evening.
Once again Mark Wood's outright pace and hostility came to the fore – he picked up four wickets to finish with a career-best match haul of nine for 100 – while man-of-the-series Ben Stokes broke both of the Proteas' biggest partnerships in his latest match-turning intervention.
Add in another 90mph option in Jofra Archer, who took six wickets in the first Test before being laid low by an elbow injury, and England suddenly look like the kind of side who can challenge Australia Down Under.
Last time they tried it ended in a chastening 4-0 defeat, but none of Wood, Archer or Stokes were around then and will surely form the cornerstone of the side come 2021-22.
"We'll try not to look too far ahead but we've got a great template to work around and it's nice to see it falling into place," said Root.
"There's a long way to go between now and then. But they would have made a big difference last time, I do believe that. (Pace) is something you need in those conditions.
"It does give us confidence and it gives us knowledge of how to perform on wickets that might be slightly similar."
Stokes, who missed the previous Ashes tour due to the fallout from his scuffle outside a Bristol nightclub but went on to play a starring role in last summer's 2-2 draw, has also got Australia in his sights.
"Obviously we're building for that series," he said.
"Having Woody and Jofra on the pitch at the same time, it would be very, very exciting to see what would happen in Australia. To have them in the same attack brings out the best in both of them. If they are both fit and raring to go when we go out for the Ashes, then that will be good."
Meanwhile, South Africa captain Faf du Plessis insisted there was "nothing malicious" in his collision with Jos Buttler, the final flashpoint of a hard-fought and occasionally ill-tempered series.
After fending away a Stokes bouncer with the handle of his bat, Du Plessis was hit on the pads by a throw from Sam Curran and became involved in a tetchy exchange with Stuart Broad.
England wicketkeeper Buttler found himself in the crossfire and was nudged by Du Plessis' shoulder as their paths crossed.
"That's part of my character, I'm always involved in a little bit of something somewhere in a game," he said.
"It's not like I am looking for it, but if it comes my way I won't back down. I don't think we knew we touched each other. It was just myself and Broady having a go at each other. I think Jos was just trying to get in between myself and him. There was nothing malicious. It just got a bit heated."
Du Plessis found an ally in Root, who moved to dampen down post-match chatter about the subject.
"There was nothing to it whatsoever. Honestly, it was absolute handbags," he said.
"I'm not worried at all. He didn't exactly knock him over did he? In fact I thought Faf was probably using is as an excuse to get himself going and get himself in a contest."