OXFORD United slumped to their third successive defeat at the Kassam Stadium as Southend United came from behind to take the points.

Barry Corr landed the sucker punch seven minutes from time for a visiting side who had played for an hour with ten men following Gary Deegan's red card.

It was 1-1 when the midfielder picked up his second booking, with Callum O'Dowda's opener cancelled out by David Worrall.

Sam Long headed United in front on the stroke of half-time, but they could not make the extra man pay after the break.

Joe Pigott headed in an equaliser three minutes after the restart and after hanging on in the face of the hosts' pressure, the visitors nicked it through Corr.

The manner of the defeat will take some getting over and left Michael Appleton's men just three points above the drop zone.

Long and O'Dowda made up half of United's four changes in the starting line-up.

Michael Collins and Will Hoskins, the latter making his first start since the away game at Southend in September, also came into the XI.

United had lost their previous two games at home and they did not make a promising start.

It took an excellent save from Ryan Clarke to deny Worrall's header in the opening 30 seconds.

The goalkeeper almost undid his good work at the resulting corner, dropping the set piece before diving on the loose ball just in time.

United have got used to seeing most of the ball in their games this season, but they were on the back foot early on.

Southend pushed wing backs Long and Tareiq Holmes-Dennis into retreat, effectively giving United a back five, while Andy Whing and Collins were also forced deep.

That left just Hoskins, O'Dowda and Danny Hylton to cause problems going forward.

It was not ideal, but two of them combined to open the scoring in the 13th minute.

Hoskins showed his class with a clever disguised pass which released O'Dowda, who kept his composure impressively to roll a finish into the net.

It was just what United needed, but they were quickly on the defensive again as Southend kept finding space out wide.

While there were no shortage of bodies wearing yellow in the middle, they looked edgy when the ball was delivered.

One Worrall cross flustered both Chey Dunkley and Johnny Mullins, before Whing finally cleared.

It was inviting pressure and United still lacked organisation when Southend drew level, on 24 minutes.

Ben Coker found space on the left and swung in a cross for Worrall to plant a header past Clarke from close range.

It nearly got worse for the home side, but Joe Pigott headed over at a corner when he should have done better.

Southend were on top, until Deegan's rush of blood to the head in the 33rd minute.

Already booked, he dived in crudely on Collins, who was left writhing in pain.

Referee Christopher Sarginson had no doubts in branding the second yellow card.

Buoyed by the extra man, United finished the half strongly.

As the game drifted into stoppage time O'Dowda had a crack with his right foot, forcing Daniel Bentley to tip over the bar.

O'Dowda took the corner himself, picking out Long to head in for his first senior goal.

United boss Michael Appleton made an attacking move at the break, bringing on Patrick Hoban for his debut, replacing the nervy Dunkley.

It meant a switch to 4-2-3-1, but before it had any time to take effect Southend were level.

Coker was again the provider, crossing for Pigott to head into the net after getting in front of Holmes-Dennis.

It was a rare foray forward for the visitors, who retreated once they had something to protect.

For a long spell it was a repeat of the second half in United's previous home game, against Cheltenham.

There was no shortage of effort, but in their haste there was a lack of quality.

It took until the final quarter of an hour for Southend to really come under sustained pressure.

They looked certain to score with one attack, when Whing intercepted and freed Hylton.

The striker's low cross fell for Hoban to have a shot blocked and the ball fell to Wes Burns, whose header was cleared off the line by Jack Payne, just on as a substitute.

Another scramble quickly followed as Hoban once again had an effort smothered and this time Burns could only head wide.

Southend were hanging on, but with seven minutes left they mounted an attack to stun the home crowd.

Coker notched up his third assist of the afternoon, crossing for Corr to turn a scruffy shot into the far corner of the net.

It was the cue for hundreds of United fans to head for the exits.

On the pitch the side attempted to salvage a late equaliser.

Several corners came and went, with Whing coming agonisingly close with a deflected shot which had Bentley beaten but dropped wide.

Their best chance came in the last of the five minutes added on when Mullins found himself one-on-one with Bentley, who smothered his shot.

The final whistle swiftly followed, prompting several U's players to sink to their knees in disbelief at the result.

Oxford Utd: Clarke, Mullins, Dunkley (Hoban ht), Wright, Long (Meades 70), Whing, Collins, Holmes-Dennis, O'Dowda, Hylton, Hoskins (Burns 54).

Unused subs: Crocombe, Ruffels, Ashby, Campbell.

Southend Utd: Bentley, White, Thompson, Binnom-Williams, Coker, Worrall (Payne 77), Leonard, Deegan, Atkinson, Pigott (Timlin 62), Cassidy (Corr 62).

Unused subs: P Smith, Prosser, Weston, Coulthirst.

Attendance: 7,207 (631 visitors).

Referee: Christopher Sarginson.