A NIGHTMARE spell just before half-time cost Oxford United as their unbeaten Sky Bet League One home record was ended by AFC Wimbledon.

Already trailing to Tom Elliott's 20th-minute header, Michael Appleton's side conceded twice more in the 43rd and 47th minutes.

There was controversy surrounding the first of those, with a dangerous-looking challenge by Dean Parrett on Wes Thomas going unpunished before Darius Charles curled home.

And with the U's still reeling, a third goal from Andy Barcham gave them a mountain to climb.

A Charles own goal four minutes into the second half gave them hope, but United could not find another breakthrough as their poor run in front of the TV cameras continued.

Appleton made two changes from the starting line-up at Bolton last weekend, rewarding the two substitutes who came on that day and made such a difference.

Wes Thomas was handed a role alongside Kane Hemmings in attack, while Alex MacDonald came in for Joe Rothwell in a 4-4-2 system.

Marvin Johnson was the other player to make way.

A scrappy start to the game saw neither side able to string any fluent passing together.

Both defences, however, looked vulnerable and from slips, Wimbledon winger Barcham twice threatened - once with a cross and then a shot that was comfortable for Simon Eastwood.

MacDonald looked lively for United, and from his cross, Hemmings tried but failed to get a shot away.

Both Wimbledon strikers were booked in quick succession, Elliott for a crunching challenge on Chey Dunkley and Lyle Taylor for diving.

The latter was a let-off for United, with Joe Skarz slipping to allow Taylor in behind. But after the ball ran away from the striker, he went down and was shown the yellow card by referee Darren Deadman.

One MacDonald cross then caused chaos in the Wimbledon box, but Thomas and Hemmings both saw efforts blocked.

The game's first corner came in the 20th minute and saw Wimbledon take the lead.

A deep cross was headed back across goal by Charles and Elliott climbed the highest to nod past Eastwood from six yards.

United supporters started a minute's applause in memory of Lewis Mangan, a big U's fan who was tragically killed recently, but it could not get their side going.

Several misplaced passes put their back line under pressure, but without Wimbledon really threatening to double their lead.

Barcham and Jake Reeves both hit shots that Eastwood gathered with ease, while MacDonald fired over for United.

The closest Oxford came to levelling was when Liam Sercombe stabbed an effort towards goal, but it trickled inches wide of the target.

Chris Maguire went down looking for a penalty, but the game's controversial moment came two minutes before the break.

Parrett went in extremely hard on Thomas on the edge of the United box.

He won the ball, but both feet appeared off the ground.

However, referee Deadman saw nothing wrong and as the ball broke to Charles, he curled a lovely effort into the top corner.

United's players and supporters voiced their displeasure at the official, but worse was to follow.

Still rattled, Sercombe lost the ball breaking forward and MacDonald was far too weak in the tackle, allowing Reeves to break forward.

The Wimbledon midfielder then played a lovely ball into the path of Barcham, who slotted past Eastwood to put the hosts 3-0 ahead.

The Kassam Stadium was rocked, but surprisingly Appleton decided against making any changes at half-time.

His decision looked justifed when United gave themselves a lifeline just four minutes after the restart.

Maguire burst into the box on the right and drilled in a low cross that was turned past his own goalkeeper by Charles.

Minutes later Thomas went down in the box looking for a penalty, but Deadman again waved away the appeals to the annoyance of the home crowd.

Tempers began to flare as the referee frustrated both sides with a series of baffling decisions.

But one he did get right was awarding United a corner in the 57th minute following a Hemmings run.

From Maguire's cross, a Phil Edwards header was nodded off the line by Barry Fuller. From the follow-up, an off-balance Thomas hooked over the bar from six yards. It was a huge let-off for the visitors.

Appleton sent on Dan Crowley and later introduced Rothwell and Johnson, but it was to no avail.

Disappointingly United could not trouble James Shea in the Wimbledon goal, failing to force the keeper to make a save.

Wimbledon threatened to make the scoreline worse with several counter-attacks, but had done the damage in the opening period.

For United, it was an afternoon to forget.

Oxford Utd (4-4-2): Eastwood, Edwards, Raglan, Dunkley, Skarz (Rothwell 75), MacDonald, Lundstram, Sercombe (Johnson 75), Maguire, Hemmings, Thomas (Crowley 64).

Subs: Brown, Nelson, Ruffels, Taylor.

Booked: Dunkley, Johnson.

AFC Wimbledon (4-4-2): Shea, Fuller, Meades, Robinson, Charles, Parrett (Egan 80), Reeves, Bulman, Elliott (Barnett 67), Taylor (Poleon 84), Barcham, Subs:McDonnell, Nightingale, Francomb, Robertson.

Booked: Elliott, Taylor, Shea.

Referee: Darren Deadman (Cambridgeshire).

Attendance: 7,742 (531 from Wimbledon).