After a second equaliser by their substitute Andy Walker 13 minutes from the end of normal time, they did enough to frustrate an increasingly desperate home side, surviving the sending-off of Nick Henry 10 minutes from the end of extra time for a mad moment in which he kneed the grounded Mauricio Taricco.
The closest Ipswich came to restoring their lead turned out to be the free-kick by Steve Sedgley in the last minute of normal time which bounced off a post. Thus the visitors, seeking a return to the Premiership after a three-year absence, move through to meet Crystal Palace at Wembley.
Despite taking a ninth-minute lead when Petr Kachuro, the Belarussian forward, broke clear and drove the ball in off the underside of the bar, United's prospects of advancement appeared doubtful when Kelly, the Republic of Ireland keeper, was reduced to a bandaged hobbler after hurting his knee in a challenge with Niklas Gudmundsson.
United's manager, Howard Kendall, was a relieved man at the end, having chosen not to field a substitute keeper. "It was Sod's Law," he said. "We protected him well. We had to, because Ipswich are a quality side."
The home team, buoyed up by their 1-1 draw in the away leg, had been seeking a first Wembley appearance since 1978 when, as FA Cup winners, they were beaten 4-0 by Nottingham Forest in the Charity Shield.
But on a night when their manager during that era, Bobby Robson, enjoyed further success by guiding Barcelona to the European Cup-Winners' Cup, they could not gain the reward their football merited. They would have enjoyed Wembley.
Their revival after United's early blow made it seem as if they were bound for the twin towers. James Scowcroft brought the scores level with a 32nd-minute header from Taricco's cross, and when Gudmundsson nodded them into the lead following Mick Stockwell's 73rd-minute cross to the far post, the blue and white banners were billowing in anticipation of a Wembley away-day. Next year, perhaps...
Ipswich Town (4-4-2): Wright; Swailes (Dyer, 90), Sedgley, Vaughan, Taricco; Uhlenbeek, Stockwell, Williams, Mason; Gudmundsson (Gregory, 84), Scowcroft. Substitutes not used: Forrest (gk).
Sheffield United (4-4-2): Kelly; Short, Holdsworth, Tiler, Sandford; White (Hutchison, 53), Ward, Henry, Whitehouse; Kachuro (Walker, 68), Fjortoft. Substitute not used: Nilsen.
Referee: T Heilbron (County Durham).Reuse content