England, seeking their first Test series victory in India in 21 years, go into the third and final Test at Mumbai on Saturday hoping only to square the series after the first Test ended in a draw.
Seamer Patel ended England's hopes of setting a stiff target with three quick wickets in his inspiring opening spell on Monday to finish with 4-25. He had taken three scalps in the first innings.
England could set only a modest 144-run target off 70 overs on the fifth and final day despite captain Andrew Flintoff's brave 51 under pressure. The tourists, trailing by 38 runs on first innings, were dismissed for 181 after resuming on 112-5.
India rode on opener Sehwag's 11th Test half-century to get the job done just before the tea-break, reaching 144-1 in 33 overs.
Sehwag put on 105 for the unbroken second wicket with skipper Rahul Dravid, who remained unbeaten on 42.
The Indian opener, who had failed in his previous three innings of the series, returned to form with an aggressive 89-ball knock including one six and nine fours.
Injury-hit England, who had fought well at Nagpur without key batsmen Michael Vaughan and Marcus Trescothick, had little chance of repeating their performance after their batting failure in the second innings.
Their pacemen tried hard, but found the target too small to defend on a fifth-day track which was still good for batting. They tasted just one success when swing bowler Matthew Hoggard trapped Wasim Jaffer (17) leg-before.
England always faced a stiff task after losing five wickets for 112 in Sunday's last session. Their slim hopes of matching India depended on a big partnership on Monday, but only Steve Harmison could give his captain company in a crisis.
Flintoff put on 42 for the ninth wicket with tail-ender Harmison, but it was just not enough to test India after Patel had run through the England lower-order batting.
Patel, 22, bowled wicket-keeper Geraint Jones (five), trapped Liam Plunkett (one) leg-before and yorkered Hoggard (four) in the first hour to reduce the tourists to 139-8.
Jones had begun positively, square-driving the day's first ball for a boundary before falling in the same over. He tried to fend off a rising delivery, which hit the bat and then the ground before bouncing on to the stumps.
Dravid then tried a double-spin attack on a slow turning track, but had to wait for more than an hour to break the Flintoff-Harmison stand.
Leg-spinner Anil Kumble, the fifth bowler in Test history to complete 500 wickets, got the breakthrough when he had Harmison stumped by Mahendra Dhoni.
Flintoff, with last-man Monty Panesar at the other end, went for a big shot but could only swing straight to Patel at deep square-leg to become debutant leg-spinner Piyush Chawla's first Test victim.
The England captain, who scored 70 in the first innings, hit four boundaries in his 20th Test half-century.