OXFORD United were unable to build on Chey Dunkley’s opener as Sky Bet League One leaders Sheffield United came roaring back to take the three points.

Hopes the U’s could cash in one of their games in hand to edge closer to the play-offs were boosted by Dunkley’s first-half header.

Little had gone for the visitors before the break, but the division’s top-scorer hauled them level.

Billy Sharp’s poacher’s finish at a corner levelled the scores, before the Blades struck twice in five minutes to secure the victory.

Kieron Freeman’s fortuitous shot found the far corner and the wide man was then fouled in the box by Curtis Nelson, giving Sharp the chance to double his tally from 12 yards.

Substitute Toni Martinez reduced the arrears in stoppage-time, but it proved to be just a consolation.

Spirits were boosted as soon as the teamsheet was published and showed United’s XI containing all four players who had been injury doubts.

Curtis Nelson returned at centre half, Chris Maguire and Rob Hall patrolled the flanks and top-scorer Kane Hemmings led the line.

Whether it was the injection of fresh legs or the sight of the leaders, United immediately played with an intensity which had been missing in Saturday’s lacklustre defeat to Bristol Rovers.

The Blades looked sharp early on too, with Dunkley making two vital interventions in the penalty area within the opening five minutes.

United were not slow in threatening at the other end.

Conor McAleny fired well over at the end of a swift counter-attack, before Dunkley stabbed Marvin Johnson’s low cross over the bar.

The latter chance had come from a free-kick conceded by a Jake Wright handball.

It was the centre back’s first appearance at the Kassam Stadium since ending his six years at United with promotion last summer.

The former U’s skipper’s night got worse shortly afterwards, when he sustained a head injury defending a corner.

After several minutes of treatment, he came off to leave the visitors down to ten men when defending a corner.

United took full advantage and Maguire’s whipped corner was flicked high into the net by Dunkley’s head.

Wright, whose name was applauded by home fans before kick-off, was unable to continue and got another ovation as he was guided up the tunnel.

Urged on by manager Chris Wilder, the Blades went in search of an equaliser.

They had plenty of dangerous moments probing around the U’s box, but when the ball came in Dunkley and Nelson dominated in the air.

It meant Simon Eastwood was not tested before the break, unlike his counterpart Simon Moore.

The Sheffield goalkeeper spilled a nervy sliced clearance from Chris Basham which had soared skywards five minutes before the break.

Hall’s follow-up header was cleared off the line, but referee Paul Tierney had already blown for what he saw as a foul by Hemmings on Moore.

It was the closest United came to going 2-0 ahead and they were pegged back ten minutes after the break.

A low corner was collected by Sharp, who fired in from eight yards for his 25th goal of the season.

The home side hit back with a promising spell, but just after the hour mark Hemmings was unable to convert a chance from close range which was blocked.

It was a big moment and the visitors hit back hard.

They went ahead for the first time with a slice of good fortune, when Freeman found the far corner of Eastwood’s net via what looked like an attempted cross.

Within five minutes the points appeared to be made safe.

After Nelson dived in on Freeman in the box, Sharp slammed home from the penalty spot.

United pushed in the closing stages and set up a tense finish when Martinez pulled a goal back in stoppage-time.

There were still two minutes left, but the Blades ran the clock down well to edge one step closer to the title.

Oxford Utd (4-4-2): Eastwood, Edwards, Dunkley, Nelson, Johnson, Maguire, Lundstram, Ledson, Hall, McAleny, Hemmings.

Subs used: Rothwell (Ledson 64), Sercombe (Hall 79), Martinez (Hemmings 79).

Unused subs: Stevens, Skarz, Raglan, Ruffels.

Booked: Ledson.

Sheff Utd (3-5-2): Moore, Ebanks-Landell, Wright (Carruthers 25), O’Connell, Freeman, Basham, Fleck, Coutts, Lafferty, Sharp, Hanson (Lavery 53).

Unused subs: Long, McNulty, Done, Wilson, O’Shea.

Booked: Wright, Coutts.

Referee: Paul Tierney (Lancashire).

Attendance: 8,965 (1,667 visitors).