George Dobell is a senior correspondent at ESPNcricinfo
He may have scored more than 600 runs in the series, but Virat Kohli's excellence with the bat appears to have left James Anderson cold.
Kohli, whose 235 in Mumbai has left him averaging 128.00 in the four matches so far, came into the series with a point to prove against England. In nine previous Tests against them, he averaged just 20.12 with a single score over 50.
He struggled particularly badly on the 2014 tour of England. With England frustrating him with a line outside off stump, he was drawn into dangerous, impatient strokes against the moving ball and ended the series with an average of just 13.40. Anderson dismissed him four times.
Speaking before the start of this series, Kohli said: "I can put it very simply as that was a phase I didn't perform very well, and it happened to be England. Could have been any other country in the world. I just take it as a setback in my career, and not motivate myself in a way that I have to prove people wrong or have to do something special against a particular opposition. For me, I'm playing a cricket ball, be it any game, any opposition, anywhere in the world. Those things do not change for me so I don't put those things in my head."
Kohli has made his point even more eloquently with the bat. On the same surfaces on which England have, since Rajkot, struggled, he has two centuries and four others scores of 40 and above. He has consistently proved a significant obstacle for England and, having ensured his team would leave with a draw in the first Test, made centuries in Visakhapatnam and Mumbai.
Perhaps his best performance came in the second innings in Visakhapatnam, where he made 81 out of a total of 204 despite a pitch of uneven bounce and against an England attack gaining lateral movement with the ball. It was masterful batting and further evidence that Kohli is a vastly improved player since the last time he faced England.
Anderson, however, remains unconvinced. He suggested that Kohli is not so much an improved batsman, as a batsman playing in conditions that do not exploit his "technical deficiencies".
"I'm not sure he's changed," Anderson said. "I just think any technical deficiencies he's got aren't in play out here. The wickets just take that out of the equation.
"We had success against him in England, but the pace of the pitches over here just take any flaws he has out of the equation. There's not that pace in the wicket to get the nicks, like we did against him in England with a bit more movement. Pitches like this suit him down to the ground.
"When that's not there, he's very much suited to playing in these conditions. He's a very good player of spin and if you're not bang on the money and don't take your chances, he'll punish you. We tried to stay patient against him, but he just waits and waits and waits. He just played really well."
Anderson took a similarly unflattering view of India's spinners. While R Ashwin and Ravindra Jadeja have 39 wickets between them in the series, Anderson said: "I'm not sure they're too difficult to handle."
He did admit, however, that England had endured their "worst morning of the tour from a bowling point of view" on the fourth day in Mumbai.
"It is immensely frustrating," he said. "Coming to the ground this morning, we needed to get three wickets. If we could get them we're still well in the game. Unfortunately we didn't bowl as well as we could have first thing. The ball started flying around and then they got settled and managed to put on a big partnership."
Despite going into the final day 49 runs behind and with only four wickets in hand, Anderson insisted that England still had a chance of the win they need to stay in the series.
"We're going to come and try to fight our way back into this game if we can," he said. "We're 50 runs behind. If we can bat with the positive intent we showed today, there's no reason why we can't get a hundred ahead of them and then try to put some pressure on them with the ball."