RYAN Clarke saved a penalty six minutes from time as Oxford United recorded a valuable three points against Barnet tonight.
It looked as though goals from Scott Rendell and James Constable would see the U's come from behind to take victory.
But with six minutes left, Damian Batt was adjudged to have fouled Ricky Holmes by referee Stuart Attwell, even though the offence appeared to take place outside the box.
But Clarke, who has a superb record of saving spot-kicks, kept out Izale McLeod's penalty with his legs.
After falling behind to a poor goal when Michael Hector's 25-yard effort found its way through a forest of legs after 16 minutes, United regrouped and thoroughly deserved their win, despite the late scare.
They levelled two minutes before half-time when Peter Leven found Lee Holmes in acres of room down the left, and from his pinpoint cross, Rendell - as he promised 24 hours earlier - scored his first goal for the U's.
The went 2-1 ahead 11 minutes into the second period through Constable.
Leven's free-kick led to a melee in the box, and after Rendell's shot was blocked eight yards out, the ball fell to Constable who hammered home from six yards.
Constable almost bagged his second after a mazy run, but shot straight at Dean Brill.
At the other end, former United winger Sam Deering, who was booed throughout, should have levelled, but shot wide from 12 yards with just Clarke to beat.
Boss Chris Wilder made two changes from the side that drew 0-0 at Bristol Rovers, and switched formations.
Oli Johnson and Lee Holmes came in for Mehdi Kerrouche and Mark Wilson as the U's started with a 4-4-2 system.
The first attempt on goal came from a quickly-taken Leven free-kick that was crossed by Lee Holmes, but Rendell's header went wide.
Barnet took the lead in the 16th minute through a poor goal from Oxford's point of view.
Jake Wright fouled McLeod, and when Mark Hughes took a short free-kick, Hector was in acres of space 25 yards out.
Although he didn't catch the ball cleanly, he got enough on it to drill in through a hosts of legs and past Clarke into the net.
Leven's free-kick went narrowly wide of the upright, and Johnson twice had shots that lacked power as United looked for an equaliser.
They nearly levelled when Constable dummied Liam Davis's pass, and from Rendell's lay-off, Constable drilled in a right-foot shot from 20 yard that Brill just about kept out - the ball hitting his body and deflecting over the bar for a corner.
The U's should have gone ahead less than 60 seconds later, however.
Johnson latched onto a Rendell pass and crossed for Constable, who was unmarked 12 yards out.
The ball was too far in front of him, however, but Constable retrieved it and fed Rendell, who took his time and allowed Clovis Kamdjo to block.
It wasn't long though before the U's were level.
Leven found Lee Holmes in space, and Rendell was in the right place to head home his cross.
Oxford were a whisker away from going ahead early in the second half, Johnson bursting into the area before rifling in a shot that hit the inside of the near post and somehow stayed out.
Attwell, who was forced to officiate after some poor performances in the Premier League, baffled the fans when awarding a free-kick for a two-footed tackle from Paul Downing.
It wasn't a foul, but having blown, let the player escape without further punishment.
Rendell's header from Leven's free-kick was well-saved, but two minutes later from another Leven free-kick, Constable ended up putting the U's ahead.
Deering wasted a golden opportunity, before Constable's fine run ended with a shot straight at Brill.
Barnet were there for the taking, but couldn't get the all-important third goal, and in the end were grateful to their goalkeeper for ensuring the three points.
Oxford Utd: Clarke; Batt, Duberry, Wright, Davis; Johnson (Tonkin 81), Whing (Wilson 72), Leven, L Holmes; Constable, Rendell (Worley 88).
Subs: Brown, Kerrouche. Booked: Johnson, Duberry.
Barnet: Brill; Hector, Downing, Dennehy (Hajrovic 46), Saville (Mustoe 71); Byrne, Hughes, Kamdjo (Obita 67), Deering; R Holmes; McLeod.
Subs: O'Brien, N'Diaye. Booked: Hajrovic, Obita.
Attendance: 5,848 (139 from Barnet)