LEICESTER 0, UNITED 1 (Clayton 69)
Leicester: Schmeichel, Peltier, Mills, Bamba, Konchesky, Gallagher (Schlupp 85), Wellens, Danns, (Johnson 74) King, Howard (Beckford 74), Nugent. Subs: St Ledger, Weale.
United: McCarthy, Connolly, O'Brien (Bromby 73), Kisnorbo, White, Snodgrass, Howson, Clayton, Pugh, McCormack (Brown 86), Keogh (Becchio 77), Subs: Cairns, Brown, Sam.
Referee: O Langford
Booked: Konchesky, Bamba (Leicester)
Att: 26,720 (3319 Leeds)
Extended highlights, plus reaction, plus the full 90 minutes replayed...
United manager Simon Grayson handed a debut to loan goalkeeper Alex McCarthy in place of Paul Rachubka and also recalled Andy O'Brien in place of the suspended Tom Lees.
The Leicester side included former United goalkeeper Kasper Schmeichel while ex-Leeds front man Jermaine Beckford was among the subs.
The home side were still on the hunt for a new manager, following the departure of Sven Goran Eriksson, while United went into the clash on the back of a 5-0 hammering at the hands of Blackpool.
And it was the hosts who mounted the first raid of the afternoon, David Nugent escaping the clutches of the Leeds defence inside the opening five minutes but having no one hand to square the ball back to.
Schmeichel did make the first save of the game, though, when Robert Snodgrass tested him with a low effort from distance, and Andy Keogh was also denied by some good defending when he threatened on goal.
McCarthy was called upon to make his first save on 15 minutes when he tipped over a chipped shot from just inside of the area.
United were slightly the more inventive of the two sides during a tight opening 25 minutes or so and, after a couple of good Paul Connolly deliveries into the box, Ross McCormack felt he had a good penalty shout after going to ground while going up for header.
Danny Pugh also tried his luck on the half-hour with a low shot which went wide of the upright following more constructive build-up play by Leeds. At the other end, Leicester were far more direct, and Paul Gallagher hurried a shot wide after a long punt from Schmeichel.
Gallagher also sent another shot wide of the post after some decenty play outside of the box by Leicester, and Aidy White made one excellent defensive header when another cross was sent into the box, but as the game edged towards half-time, it was fair to say that Leeds looked the more likely of the two sides.
It wasn't until the 40th minute that debut man McCarthy was called upon again and that was to get down low to a shot from just inside the box.
There were no other real opportunities as the game reached half-time scoreless, although Leicester had to clear one Leeds free-kick, and Grayson's men thwarted a quick raid by the hosts.
United had looked solid during the opening period and had tried to play the better football, although the game was finely balanced when the second half started with Leeds enjoying another spell of possession.
United almost had an opportunity when Schmeichel made a poor clearance, but Keogh was unable to get enough hook on his shot to lift it back over the Dane.
It was United's turn to do some defending when Leicester threatened and O'Brien made two great clearances, despite appearing to need treatment for a knock. From Leicester's first corner of the second period, the ball squirmed its way over the bar following a stabbed shot.
Leeds were getting men behind the ball when the hosts were in possession, and while United were intricate with the ball, Leicester moved it quickly and got men forward at pace.
On 66 minutes, United had what appeared to be a decent penalty shout waved away when a well-placed McCormack again went down under pressure while looking to get on the end of a great cross from Connolly.
But leeds were rewarded for what was shaping up into being a good away performance when the ball broke to Clayton on the edge of the box and the midfielder unleashed a thunderbolt of a strike past Schmeichel and into the top corner.
It was a wonderful goal from the youngster and put United in a great position going into the final 20 minutes or so.
Grayson made his first change on 73 minutes, Leigh Bromby replacing O'Brien, and Leicester immediately followed suit by bringing on Michael Johnson and former Leeds man Beckford, who received a great reception from the travelling fans.
Beckford's old striking partner Luciano Becchio was next to join the fray when he came on for the hard working Keogh.
The hosts started to show more urgency and Schemichel launched one quick punt from his own box to the feet of Beckford in the other, but the striker couldn't bring the ball under control and McCarthy was able to gather.
Leeds responded immediately, though, and Schmeichel had to down well when Snodgrass drilled a shot in at the near post.
It was clear United would have some defending to do during the closing stages, and Bromby's first real touch was to make an important clearance in the box.
It was equally clear that Leicester were going to leave space at the back as they pressed for a leveller and United almost made the most of one counter before Becchio was crowded out. Paul Konchesky also hacked away a Howson cross when McCormack was waiting for the tap-in.
With five minutes left, Grayson sacrificed McCormack for Michael Brown with the midfielder dropping into an anchor role as Leeds looked to secure the points.
But it was Paddy Kisnorbo who made a good clearance after Beckford had broken clear and looked to put the ball back in the box. From the corner, it was Becchio who did his defensive duties well and headed away the danger.
The referee added five minutes on at the end of the 90 to make United sweat that bit longer in the bid to record a first ever win at the King Power Stadium.
The Leeds fans, who had been terrific throughout, took that as the cue to turn up the volume and United edged ever closer to a deserved away victory.