Oxford striker James Constable netted a late second as the U's claimed a 2-2 draw which denied Barnet the chance to jump out of the League Two drop zone for the first time since February.
Fresh from a stunning 4-2 victory at Gillingham, the relegation-threatened Bees continued their revival with Clovis Kamdjo netting in the 11th minute, only for Constable to equalise moments later.
Mark Hughes put Barnet back in front on the hour and on course to move out of the bottom two, only for Constable to pounce again with 12 minutes left.
That leaves the Bees, who could have taken the lead a lot earlier through Mark Marshall, still second bottom but just one point adrift of Northampton with two games remaining.
Kamdjo made up for Marshall's early miss, meeting Mark Byrne's curling free-kick at the far post to put Barnet ahead, but Constable pulled Oxford level when unmarked in the 16th minute.
Right-back Kamdjo tried his luck with an audacious 25-yard curler shortly after, before Hughes put Barnet ahead following the break courtesy of a fortuitous cross-come-shot.
That temporarily moved the Bees out of the bottom two but, with pressure building, Constable tapped in Josh Payne's cross from close range to earn Oxford a draw.
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