Fifth one-day international, Cuttack: India 273-4 (43.4 ovs) bt England 270-4 (50 ovs) by six wickets
Sehwag's masterful innings gave India an excellent platform in the run-chase
Kevin Pietersen hit a century but India eased to a six-wicket win over England with 38 balls left to take a 5-0 lead in the seven-match one-day series.
Pietersen scored 111 off 128 balls and shared 112 in 116 with Owais Shah (66) as England posted 270-4 in Cuttack.
But in reply Virender Sehwag and Sachin Tendulkar amassed 136 inside 20 overs, Sehwag (91) firing 15 fours and a six.
Two wickets fell in two balls before Mahendra Dhoni (50) compiled 94 with Suresh Raina, who was unbeaten on 53.
Pietersen's landmark century was the first by an England player for 14 matches and the first overseas by an England skipper, which helped the team pass 250 for the first time in the series.
However, critics still smarting from the decision not to have nets on Tuesday were given further ammunition by another perplexing batting line-up.
Alastair Cook was recalled to the side for his first one-day international match since June and Paul Collingwood, with only 44 runs to his name in the series, was promoted to number four.
Cook cut his fourth ball for four but in the sixth over he tried a similar shot to a wide one and edged to slip.
Partner Ravi Bopara survived a confident lbw shout before he had scored, but went on to play some attractive shots in his 24.
Pietersen was full of intent early in his innings, getting off the mark with a top-edged hook over the wicketkeeper's head, but was soon playing shots of more authority as 68 were scored inside the first 10 overs.
Shah gave England much-needed impetus with another fine innings
However, Bopara drove to backward point and the next powerplay chunk produced only 13 runs in the five overs as Collingwood looked painfully out of touch.
To his credit he scraped his way to 40, frequently employing the chip into the leg-side, and shared 89 in 20 overs with Pietersen.
Andrew Flintoff arrived at the crease in his cap expecting spin, but Dhoni double-bluffed him by using Ishant Sharma, and Flintoff edged his third ball to slip.
Pietersen worked the ball expertly through the leg-side and passed 3,000 one-day runs with a six down the ground, but was becalmed in the closing stages of the innings.
Having hit the first ball of the 35th over for his ninth four, it took until the penultimate ball of the innings for his next boundary.
England took their batting powerplay in a strong position at 196-4 after 40 overs with the captain and Shah both going well.
However, Zaheer Khan and Sharma gave them little to hit in those five overs as only 32 were added.
England were fortunate that Shah played another innovative innings, mixing forceful strokes with unusual ones, but were left wondering how many more they might have scored had he batted higher up the order.
India coasted to 62-0 from the first 10 overs, and Pietersen chose not to take the powerplay and brought slow left-armer Samit Patel into the attack.
That plan lasted all of an over as Flintoff came back and the fielding powerplay was taken.
With the fielders still up spinner Graeme Swann was risked, and it was a gamble that backfired as Sehwag cut loose and 21 came from the over.
A direct hit from Bopara at cover would have run out Tendulkar, but the only problem for the Indian strokeplayers appeared to be the surface, with several deliveries keeping low as the evening dew began to take effect.
However, Sehwag had no trouble in wristily carving Stuart Broad to the fence before driving the next ball effortlessly past the bowler for four more.
He moved into the 90s in the 23rd over with one of his few false strokes, an inside edge, going past the stumps for four off Bopara.
Tendulkar completed a remarkable 90th one-day fifty before he was bowled by a slower ball from Steve Harmison.
There were waves of noise when the boundaries were flowing but total silence ensued as Yuvraj Singh got a leading edge and Bopara took a sharp return catch.
From the first ball of the next over Broad nipped one back to trap Sehwag pushing forward, although the only way the ball would have hit stumps was if another set had been placed alongside.
The next passage of play was also quiet, as Dhoni and Raina for once were forced into a period of consolidation.
Swann returned and might have had Dhoni stumped, the captain given the benefit after a series of replays, while a leading edge spooned to safety over the spinner's head.
But the required rate was always well below the current one and the batting powerplay was still in hand.
The persevering Swann managed to oust Dhoni after the captain had recorded his 25th half century, but a beleagured England were left with the very real prospect of suffering their first 7-0 whitewash.