England 578 (Root 218, Sibley 87, Stokes 82) and 178 (Ashwin 6-61) beat India 337 (Pant 91, Sundar 85*, Pujara 73, Bess 4-76) and 192 (Kohli 72, Leach 4-76) by 227 runs
England inflicted a 227-run defeat on India in Chennai thanks to a dominant fourth-innings bowling performance, with Jack Leach and James Anderson taking seven wickets between them on the final day as they wrapped up victory before tea.
After removing Rohit Sharma on the fourth evening, Leach struck the first blow on the fifth morning by drawing an edge from Cheteshwar Pujara, and returned to help mop up the tail, but it was Anderson's spell before lunch that ripped out India's middle order and set the win in motion.
With the ball reverse-swinging and keeping low from a length, Anderson sent the off stump cartwheeling out the ground twice in his first over of the day to remove Shubman Gill and Ajinkya Rahane, and induced a leading edge from Rishabh Pant to leave him with figures of 5-3-6-3 in a spell that defined the day.
Despite a near-faultless innings of 72 from Virat Kohli, India's chances were quashed by the loss of five wickets in the first session, and after a grubber from Ben Stokes snuck under Kohli's bat, Leach and Jofra Archer finished the job to seal a sixth consecutive away win for England. This was only India's second defeat at home since their 2-1 series loss to England in late 2012, and leaves them needing at least two wins and a draw in the remaining three matches if they are to reach the inaugural World Test Championship (WTC) final.
Gill had started the day by working the first ball he faced for four through midwicket, punishing Leach as he dropped a fraction short. But if India had hoped that would be a sign of things to come, there was evidence early on that the pitch would not prove straightforward: Gill had to jam his bat down on a shooter from Leach, and was beaten by some extra bounce from a length two overs later, while Archer found inconsistency in carry while bowling to Pujara.
Pujara's wicket looked the crucial one, after his rearguard efforts in Australia and with his impeccable record against left-arm spin. But he was gone within half an hour: he closed the face looking to work Leach into the leg side, but the ball turned and bounced to take the shoulder of the bat and loop up to Stokes at slip.
Gill continued to score freely, picking off Dom Bess' loose balls and reaching a fluent half-century, at which point Joe Root threw the ball to Anderson, hoping he could get it to reverse-swing. He could. His second ball was full, and hooped in from outside off stump. It breached the gap between Gill's bat and pad, and crashed into the off stump, sending it cartwheeling and England into exuberant celebrations.
But Anderson was not content with a single breakthrough. The fourth ball of his over rapped Rahane on the pad, again hooping in towards the stumps from wide on the crease and keeping low. Umpire Nitin Menon was unmoved so England reviewed, and while the ball was shown to have been crashing into the base of middle, the decision was upheld with its impact shown as 'umpire's call'.
There was no doubt about his next ball. Anderson again went very full, anticipating prodigious movement from the reversing ball, and again snuck through the gap between bat and pad. The ball kept low once more, pinging into Rahane's off stump and sending it out of its groove. It left India four down within the first hour, and with their hopes of saving the game hanging by a thread.
Anderson struck once more in his spell, with Pant unable to continue his rich vein of form. Having reversed the ball both ways, Anderson ran his fingers down the side of the ball when pitching full, and Pant, shaping to work to leg, could only miscue to Root at short cover via a leading edge.
Bess returned after an inconsistent first spell, and once Kohli - who looked in fine touch right from the start of his innings - had hit him for four off a full toss, he drew a thin edge from Washington Sundar, prodding forward outside off, who was given out on review.
Kohli represented India's final hope, putting away three consecutive full tosses from the wayward Bess before lunch and lofting Archer down the ground for a crisp four. Archer rapped Ashwin on the glove before striking him on the wrist and the badge of the helmet, but India went into the break six down.
After lunch, Leach again found extra bounce from a length to get Ashwin caught behind, shaping to cut but only managing to glove through to Jos Buttler behind the stumps. Kohli had not put a foot wrong, but was undone by a shooter from Stokes which skidded out of the rough and knocked back the off stump, and after Leach had Shahbaz Nadeem caught at silly point - via a deflection from Buttler - to take his fourth and England's ninth, Archer sealed the win as Jasprit Bumrah edged behind.
England were buoyant, winning their sixth Test in Asia on the bounce and extending their unbeaten run under Root's captaincy to 11, helping him move level with Michael Vaughan with 26 career wins - the most by an England captain. Questions about the timing of his declaration were made academic by a clinical bowling performance on the final day, and his side are now 1-0 up in a series they went into as outsiders.
Matt Roller is an assistant editor at ESPNcricinfo. He tweets at @mroller98