Stevenage kept up their League Two play-off hopes with victory at fellow promotion chasers Oxford.
Boro took the lead in the first half when Luke Foster's cross found Harry Worley, who put through his own net.
The U's equalised in first-half stoppage time through Tom Craddock's spot-kick, after Peter Winn brought down Josh Payne in the area.
But Craig Reid latched on to Rob Sinclair's pass and coolly slotted home to give Stevenage victory.
Stevenage manager Graham Westley told BBC Three Counties Radio:
"I thought the performance was very professional, very hardworking, very disciplined and very organised.
"We started the second half on fire, we got the ball down and worked it and what a finish from Craig Reid.
"Lawrie Wilson was outstanding all night. He was out of position but it was a monstrous performance."
Oxford Utd 01 Clarke 06 Wright Booked 18 Kinniburgh 22 Worley 23 Purkiss 04 McLaren Booked 11 Clist 28 Payne Booked (Potter - 58' ) 10 Midson (Constable - 77' ) 29 Craddock (Hackney - 58' ) 32 MacLean Substitutes 21 Eastwood 02 Batt 05 Sangare 08 Heslop 16 Hackney 09 Constable 15 Potter Stevenage 16 Day 02 Wilson 04 Charles (Beardsley - 80' ) 06 Foster 14 Roberts 25 Henry Booked 21 Mousinho 24 Bostwick 10 Reid (May - 90' ) 17 Winn (Bridges - 73' ) 23 Sinclair Booked Substitutes 01 Bayes 07 Murphy 08 Long 18 Bridges 12 May 20 Beardsley 27 Maamria