Simon Grayson named the same team which performed so heroically at West Ham the previous weekend as United took on an Ipswich side who had been beaten 7-1 by Peterborough last time out.
Leeds had beaten Doncaster in midweek in the Carling Cup, and the reward of a home clash with Manchester United was revealed shortly before kick-off at Portman Road.
The game was also preceeded by a torrential downpour which made conditions greasy during the opening exchanges.
But it was Leeds who fashioned the first opening of the game, Tom Lees picking out Ross McCormack who was denied by an advancing David Stockdale. Ipswich failed to clear the resultant corner, and Robert Snodgrass came mightily close with a shot which curled just around the post.
McCormack also got up well to meet an Aidy White cross, but his header was just wide of the mark.
United were the better side during the opening 15 minutes and Max Gradel sent an effort wide after a sweeping move forward by Leeds.
Stockdale kept Ipswich in the game on 18 minutes when he pulled off another good save to deny McCormack after another good Lees ball in, and Leeds were really taking the game to the home side.
Next, Paddy Kisnorbo couldn't quite keep his header down following a Snodgrass corner while McCormack pursued an Adam Clayton ball in vain when he would have only had Stockdale to beat.
Ipswich finally fashioned out a chance on 24 minutes when Daryl Murphy teed up an advancing Keith Andrews, but the midfielder made a real hash of what was a great opportunity as he failed to control the ball.
Leeds responded immediately with McCormack winning a free-kick on the edge of the box. The Scot dusted himself down to take the set-play and saw his effort deflected over by the wall.
Undeterred, Leeds continued to pile on the pressure, Clayton next to win a free-kick on the edge of the box. This time Gradel took it and curled an effort just wide.
Just as the game was threatening to be a real one-sided affair, Ipswich carved out another opening that saw Jay Emmanuel-Thomas headed over the bar at the far post.
But, as the game headed past the half-hour, it was threatening to turn into a real battering and the reward came on 34 minutes when Robert Snodgrass sent in a cross from the right and McCormack converted with aplomb to make it 1-0.
The goal was no more than United deserved after what had been a highly impressive start to the game. Ipswich had been comprehensively outplayed during the first half and when two players collided going for a header moments before the break, it summed up their contribution to the game.
There was drama at the start of the second half, though, when Emmanuel-Thomas went in pursuit of a ball over the top before tumbling under pressure from White. The home side called for a penalty, and referee Andy D'Urso pulled out a red card for White after consulting an assistant.
The ref awarded no penalty, though, instead giving Ipswich a free-kick on the edge of the box which was dealt with.
Grayson responded by sacrificing McCormack for Andy O'Brien as Ipswich headed wide from a corner kick.
Emmanuel-Thomas limped out of the game following the incident and he was replaced by returning Portman Road favourite Jimmy Bullard.
The home crowd responded for the first time, and Ipswich had more of a spring in their step, Andrews testing Lonergan with a rasping shot from distance.
United came under a short spell of pressure, but quickly re-grouped and with less than half-an-hour remaining, it was very much a case of ensuring the numerical difference didn't count.
Leeds were getting men behind the ball when Ipswich attacked and were looking to hit the hosts on the break when in possession.
O'Brien headed one attempt clear while Clayton also made a timely block, and as the game headed into the final 20 minutes, Leeds were preserving the lead by showing a good work-ethic.
United were battling hard, but Ipswich introduced Jason Scotland in the 72nd minute and within six minutes he had made his mark by rifling home from the edge of the box to level matters. Given Ipswich's lack of potency, it was ill-deserved, but it gave United a mountain to climb in terms of picking up all three points.
The equaliser set things up for a tense finale and it was Ipswich who were looking to press for the winner. Leeds were coming under pressure and were being asked to dig deep. Kisnorbo made a good clearance, and Clayton, Lees, and Howson all made blocks.
But, there was still attacking life in Leeds, too, and one swift move forward ended with penalty claims after Gradel went down inside the box following some good play. On another break, Andy Keogh was thwarted by an Ipswich defender as he looked to pick out Gradel.
It was the home side who had the last word, though, in the last minute. Scotland laid it off to Andrews, from distance, and his shot took a cruel deflection off Clayton and looped over Lonergan into the net.
It was an ill-deserved goal for an Ipswich side who had not been in the contest until Leeds were reduced to 10 men, and the massive deflection capped off United's frustrations.
That appeared to settle the game, but United threw everyone forward, including Lonergan, for two late corners in the hope of salvaging a deserved point. Five minutes of stoppage time provided little comfort, though, and Grayson's men were left to rue what might have been after a frustrating second half proved decisive.