England captain Alastair Cook hailed his team after their remarkable transformation of fortunes in the Investec Test Series against India.

Cook admitted England were at "rock bottom" less than three weeks ago - and he faced much questioning of his own position - after losing the second Test at Lord's to fall 1-0 behind.

The mood changed with a superb win in the third Test at the Ageas Bowl and the turnaround continued with a stunning innings-and-54-run victory inside three days at Emirates Old Trafford.

England claimed nine wickets after tea on the third day to skittle India for 161 in 43 overs, just two days after the tourists were dismissed for 152.

Cook said: "We were pretty much at rock bottom at Lord's but with the glimmer of Rooty (Joe Root) scoring a lot of runs, Gaz (Gary Ballance) coming in and doing really well and the younger guys who had come into the side.

"It was a matter of the senior guys stepping up to the plate, and we have done that in the last couple of games.

"We have stuck together well in some tough moments this summer.

"We knew it would turn if we kept doing stuff but the longer we went on not winning games of cricket, the harder that became.

"To win at Southampton was massive and the challenge this week was to match the intensity. To set the tone like we did in that first morning - we didn't look back."

India never sufficiently recovered to challenge England after crashing to eight for four on the first morning and their performance in the evening on day three was even more humbling.

Cook said: "You don't often get nine wickets in a session against any team.

"We got on a roll straight after tea and took five wickets. Then we knew we could get the job done by tonight.

Moeen Ali played a huge part in India's demise, claiming four for 39 with his improving off-spin.

The Worcestershire all-rounder had been regarded as a part-time spinner at the start of the summer but his latest effort came after a match-winning six for 67 at Southampton.

Cook said: "Part of their game must have been to attack Moeen.

"That is what they have tried to do, but Moeen has improved rapidly. I haven't seen an improvement like that in an international player.

"He's a canny operator. He's learnt how to bowl on flat wickets when he's got to hold an end, but when it's spun he's bowled well and got a really good wickets."

India captain MS Dhoni laid the blame for the defeat at the feet of his batsmen.

The tourists recorded a world-record equalling six ducks in the first innings and the top order again failed in the second.

Dhoni said: "The batting department will have to improve, especially as we are playing one bowler more.

"The top five or six will have to get more runs so the bowlers will feel comfortable.

"It is important is to put runs on the board and to some extent the Lord's win and the performance of (numbers) seven, eight, nine, 10, 11 have camouflaged the problem. The top order is not really performing so well.

"The one good thing we saw in this Test match was there is help there for the fast bowlers. They took wickets of the opposition, which is very important to win games."

Dhoni admitted the first session, after he had won the toss and chosen to bat, badly damaged his side's chances.

He said: "That had a very big impact on the game, but a lot of things had consequences in this match.

"Hopefully we will learn from this and move into the next one, which will be very important for us."