Second-half goals by Matthew Etherington and Christian Dailly finally ploughed the Tractor Boys into the ground as the Hammers booked their place in the Division One play-off final at the Millennium Stadium on Saturday week.
Knowing they were just 90 minutes from a possible return to the Premiership, Town, carrying their precious one-goal lead from the first leg at Portman Road, had made just one enforced switch as Shefki Kuqi came in for the injured John McGreal while West Ham were unchanged.
In a throwback to the 1950's, the sides had been led out by a huntmaster blowing the traditional horn and, indeed, both teams were quickly giving chase for that final showdown with ex-Hammer Iain Dowie's Crystal Palace.
Certainly, when Saturday's goalscoring hero Darren Bent galloped away after just two minutes Hammers looked in serious trouble, but the Town striker's shooting boots deserted him as he wastefully dragged his shot across the face of goal with just the exposed Stephen Bywater to beat.
Roared on by the most vociferous crowd at Upton Park for many seasons, West Ham were quickly looking menacing too as Marlon Harewood charged upfield and fired over, before the ghosting Steve Lomas met Etherington's cross with a side-footed ten-yard volley that rocked the bar.
Having been saved by the woodwork, Kelvin Davis then brilliantly clawed away Bobby Zamora's point-blank 11th minute header and, midway through the half, the Town keeper proved equally agile when he acrobatically turned aside Dailly's sizzling 30-yarder.
Although Bywater was forced to hold Jermaine Wright's half-volley at full stretch, Davis had still been by far the busier in an opening period that saw the Eastenders leave the field wondering what more they had to do to claw themselves level on aggregate.
But just five minutes after the restart they got a resounding answer. For when Michael Carrick cut a short corner back to the unmarked Etherington on the left-hand corner of the Tractor Boys' penalty area, the former Spurs wide-man sent an unstoppable, rising shot through a crowd of bodies and under the right-hand angle of Town's groping goalkeeper.
Game on. Alan Pardew upped the stakes with the introduction of Brian Deane for the tiring Zamora and the nomadic veteran striker was soon making his presence felt with a nod-down that David Connolly spooned over.
Midway through the half, Connolly was presented with another glorious chance to double West Ham's lead when Harewood unselfishly played him in but, yet again, his close-range shot was wastefully high.
On 71 minutes though skipper Dailly showed his team-mates the way to goal, when he side-footed home from eight yards after Etherington's well-flighted corner painfully ricocheted into his path via his marker.
A tense finale played out amidst a deafening atmosphere was inevitable, but, as stoppage time approached, Ian Westlake almost silenced the whole of east London with an 18-yard screamer that crashed back off Bywater's right-hand upright.
The width of the post showed just what a fine line there is between success and failure and as heartbroken Ipswich return to leafy Suffolk cursing their luck, Hammers now head to Cardiff for that crunch showdown with Palace.