Barry Corr came off the bench to give 10-man Southend a thrilling 3-2 victory at Oxford after they trailed at half time.Corr turned in Barry Coker's left-wing cross in the 82nd minute, just moments after Oxford twice had efforts cleared off the line.Shrimpers boss Phil Brown was sent to the stand late on for persistent encroachment on to the pitch, but he could celebrate a fine win which saw his side play for an hour with a man short.Callum O'Dowda fired the U's in front in the 13th minute with a clinical low finish from Will Hoskins' smart lay-off.But Southend were level in the 24th minute when David Worrall powered a free header past keeper Daniel Bentley from Coker's pinpoint cross.Southend then had Gary Deegan dismissed for a second yellow card following a late challenge on Michael Collins.From O'Dowda's 45th-minute corner, right-back Sam Long headed in for his first Oxford goal to make it 2-1.Yet the visitors hit back three minutes into the second half, with another fine delivery by Coker headed home from close range by Joe Pigott, and it was from another Coker cross that Corr settled it.