Root (88) fell 10 runs short of his fellow Yorkshire batsman Michael Vaughan’s England record tally of 1,481 runs in a calendar year - but did take his uncanny sequence of at least a half-century in each Test he has played against India to 11 since he made 73 on debut in Nagpur in 2012.
The riches of his and Moeen Ali’s stand of 146 seemed a world away after England won the toss for the fourth time in five matches but then lost both openers in the first hour to falter to 21-2 at the MA Chidambaram Stadium.
Those early indications of yet another struggle, in keeping with England’s tour-long strife on the way to series defeat and a 3-0 deficit with just this final match remaining, were gradually dispelled.
The third-wicket partnership was a slow-burner, in stifling conditions, but a precious and increasingly proactive one after Alastair Cook and Keaton Jennings’s early departures.
Moeen (63) had only seven from 44 balls at lunch. But on the way to 50 from 111, he brought up the half-century stand with a swept four off Ravi Ashwin - a deed Root would repeat within the hour to take their alliance into three figures.
By the time the vice-captain fell, caught-behind from an under-edge behind on a sweep at Ravindra Jadeja detected only by technology on DRS after an initial not-out verdict, he had hit 10 fours from 144 balls.
He cut a frustrated figure too, though, mouthing his irritation after the decision was overturned and therefore meant he had turned only three of his last 17 Test fifties into hundreds.
Moeen still had a shot at three figures, as he and Jonny Bairstow closed out the session.
Cook, who will be 32 on Christmas Day, was responsible for the first notable statistic of the day when he became the youngest man to reach 11,000 runs with a push off Umesh Yadav to cover - where a misfield brought him two to start the Test.
There were to be only another eight for him here, though, before he fell to his tour nemesis Jadeja - who got him for the fifth time in the series via an edge to slip on the front-foot defence.
Jennings had earlier added just a 17-ball single, following his maiden hundred and then golden duck on debut last week, when he edged a drive behind at the ultra-economical Ishant Sharma from round the wicket.
Moeen needed a moment of fortune, when his chip over midwicket off Jadeja got him off the mark but only after flicking through KL Rahul’s outstretched hands.
Thereafter, though, he and Root took over to put England in relative rude health.
England brought Liam Dawson into this match, their fifth debutant in seven Tests since leaving home for Bangladesh two-and-a-half months ago.
Stuart Broad returned from injury in place of James Anderson, sitting this match out with “body soreness” - while India made two changes, Ishant in for Bhuvneshwar Kumar and Jayant Yadav missing with a hamstring niggle as leg-spinner Amit Mishra came back.
A minute’s silence was held before play, and both teams wore black armbands, in memory of the victims of Cyclone Vardah - which hit Chennai on Monday - and prominent politician Jayalalithaa Jayaram, who died last week.