Man of the Match Bell made 86 not out and Strauss 78, the pair putting on 110 runs for the second wicket at Trent Bridge to ease the home side to a comfortable eight-wicket win yesterday.
Kevin Pietersen was the other not-out batsman with 41 off 48 balls in England's total of 237 for two in 46.2 overs.
Pakistan, who made 235 for eight in their 50 overs, lead the series 2-1 with a game to play.
It was England's first one-day win against a leading side in 10 matches. They lost their previous two series 5-1 against India and 5-0 against Sri Lanka.
The high drama of the day-nighter came at the end of the Pakistan innings, when all rounder Abdul Razzaq produced an extraordinary display of clean leg-side hitting to give his side some hope after the failure of their much-vaunted top order.
Razzaq, who finished with 75 not out off 72 balls, cross-batted five sixes and two fours during the final 12 balls of the innings, with 69 runs of Pakistan's 235 coming off the last four overs.
England, however, who lost the toss for the fourth time in a row, never looked in any real trouble - apart from when facing the excellent Mohammad Asif -- as they coasted home with 22 balls to spare. The final game of the series at Edgbaston is scheduled for tomorrow.
Pakistan never got going at the Nottingham venue after losing two wickets to seamer Jon Lewis with 17 runs on the board. Younis Khan, one of the big Pakistan wickets, lasted six balls before groping forward at an outswinger and edging to Paul Collingwood at second slip.
The matchwinner with a century at Southampton three days earlier, Younis failed to get off the mark this time.
Pakistan's other major problem was Mohammad Yousuf's sudden loss of touch. One of the world's leading batsmen and with an average of 109 in the series before yesterday, he seemed unable to get the ball off the square before his demise after a tortured innings of 29 off 80 balls.
That sparked the fall of three wickets for two runs in 11 deliveries. Yousuf fell to part-time left-arm spinner Michael Yardy, bowled by a flat, fast delivery speared in towards his pads.
Yardy, who took three for 24 off 10 overs on his debut, then caught Shoaib Malik off a chipped return catch to complete a double-wicket maiden.
Next over Inzamam-ul-Haq did the same to off spinner Jamie Dalrymple to make it 117 for six and all but settle the result.
The Pakistan captain made a polished 47 off 56 balls but received little support from his team mates until Razzaq's finale. The last two deliveries of the innings, from Lewis, both ended in the stands.
Ed Joyce went cheaply to fast bowler Asif before Strauss and Bell laid the foundations of England's winning reply.
They rarely looked in trouble, although there was one moment of controversy, when Strauss edged Asif low to Inzamam at slip when he was on five. Inzamam was furious when the decision went to the third umpire, who reprieved the England captain.
The only fireworks came from Bell. He managed three consecutive fours off both Razzaq and Rana Naved-ul-Hasan and reached his half-century off 53 balls.