India v England: Kevin Pietersen innings decisive - Alastair Cook
Alastair Cook says Kevin Pietersen was the difference between the sides in England's 10-wicket win over India.
Pietersen made a superb 186 to set up a series-levelling victory inside four days in the second Test in Mumbai.
Spinners Monty Panesar and Graeme Swann shared 19 wickets, but captain Cook said: "The innings that changed the game was that one.
"That was sensational. He took the game away from India and that's why you want him in your team."
Pietersen came in for criticism after making 17 and two in the defeat in the opening Test in Ahmedabad, his first since being dropped this summer for sending "provocative texts" to South Africa players.
"Pietersen's brilliant innings infused England with a confidence that spilt over into the way they approached their second innings run chase. After everything that happened in Ahmedabad and then losing the toss, this is a serious win."
"He held his hands up; he didn't play two of the best shots he's ever played," added Cook. "(But) you can see how damaging he can be.
"Not many people in England - or the world - can play like that."
Pietersen said: "It's a great feeling to get a Test century and help us win. It's a wonderful, wonderful occasion to be standing here having won.
"It's nice to be back playing. It's special to be part of this team and the dressing room is certainly united."
It was only England's second victory in 14 Tests in India stretching back to 1985 - and was achieved after they lost the toss for a second successive game and were asked to bowl first on a pitch seemingly tailor-made for India's three spinners.
"It's been an amazing three days," said Cook, whose 122 helped England establish a crucial first-innings lead of 86.
"Last week was a tough week for us and we had a lot of negative press over the way we played.
"We've stuck to our guns. We know we can play well in these conditions. This week we did.
"I can't thank the lads enough for the effort they put in and the belief they showed."
Panesar took five wickets on a thrilling third evening to undermine India's second innings. He finished with 6-91 and 11 wickets in the match, while Swann claimed match figures of 8-113.
"Monty and Swanny are world-class spinners," said Cook. "They were brilliant. The way they bowled as a partnership, they never let India get going."
England head to Kolkata for the third Test starting on 5 December with renewed hopes of a first series win in India since 1984-85.
But Pietersen warned: "We're not going to get ahead of ourselves.
"History doesn't help us, certainly. These are their conditions and we're going to have to play great cricket in Kolkata and in Nagpur."