Root’s two centuries were cornerstones of victories in Cardiff and then Nottingham, where England regained the urn after their 5-0 whitewash in Australia two winters ago.
There was an extra accolade for England’s middle-order linchpin too when the latest International Cricket Council rankings revealed he has deposed Australia’s Steve Smith as the world’s No 1 Test batsman.
His motivation throughout, though, has dwelt in those deeply uncomfortable memories not just of England’s crushing defeat down under but his part in it.
Root arrived in Australia in October 2013 as England’s rising star, expected to continue as captain Alastair Cook’s partner at the top of the order.
By the final Test, he was dropped after a run of poor form – having from the outset been shunted down the list in favour of Michael Carberry.
The 24-year-old Yorkshireman has found a new place for his country, first at number five and now four – and as Cook’s vice-captain too, is seen by many as the foundation on which England will build their team for years to come.
His 2015 Ashes average stands at 73.83 after four Tests, is almost 35 an innings ahead of the nearest Englishman beneath him and almost 30 more than Smith’s too – despite the Australian’s double-century at Lord’s. It is a world away from his 192 in eight innings before making way for Gary Ballance in Sydney 19 months ago – an experience Root can still not forget.
Recalling it again in the glow of England’s series-clinching innings victory at Trent Bridge, he said: “I can’t speak for other people, but personally that was the inspiration.
“Knowing what we went through there – all that hurt and pain, all the stuff we’ve had to overcome since then – I think the way we have handled ourselves has been brilliant, and it’s shown by the performances we’ve put in on the field.”
It has brought elation in place of the dejection which resulted in a raft of management and personnel changes.
The distress was individual as well as collective, but has in time borne a much sweeter fruit.
“That was a tough tour – so when you get into a position of strength out in the middle and you know what it’s like to be on the wrong side of it, you want to make sure you drive it home,” said Root.
“You want to make sure you’re not in that position again. That’s something that has always been in the back of my mind.
“It’s definitely one of the reasons why this is so enjoyable.”
Root had restated his case abundantly before the first Investec Test in Cardiff – where he made 134 and 60 – and had confidence he was not the only one able to rise to a new challenge.
“I definitely knew at the start of the series we were capable of achieving what we have,” he said.
“Everyone, throughout the series, has made valuable contributions along the way. It’s not been a series where one or two men have carried the team. Everyone has chipped in with performances. Going forward, that stands us in great stead.”
Some are already advocating it is time for Root to replace Cook in charge of the team. He disagrees. “As far as captaincy is concerned, Cooky has done exceptionally well,” said Root.
“He’s just won the Ashes for the second time in three attempts, so I hope he’ll be in charge of us for a long time.
“He has been a fantastic captain throughout the series and throughout this summer, as he was before that.
“There have been times when we haven’t backed him up, but thankfully this series we have and we hope that will continue.”
Root may statistically be looking down on the rest of the world’s batsmen, but he believes self-improvement is still needed and is more comfortable reflecting on England’s success than merely his own.
“My game is nowhere near perfect,” he said. “I have a lot of things I want to work on. You have personal goals. But it is nowhere near the front of my mind. It’s about having days like this and being part of something as special as this with this group of players. It’s been such a complete team performance.”