Oxford came from two goals behind to net a share of the spoils at Stevenage.
The hosts went ahead when Steve Morison's low shot flew in, but they were soon down to 10 men, Hasim Deen sent off for hitting Chris Hargreaves.
Oxford were stunned when Morison made it 2-0 from close-range, before Robert Duffy halved the deficit by lashing home from Yemi Odubade's cross.
Stevenage were down to nine when Luke Oliver was sent off for two bookings before Hargreaves levelled matters.
Stevenage: Julian, Deen, Nutter, Oliver, Henry, Miller, Johnson, Guppy (Gaia 62), Beard (Dobson 84), Boyd, Morison.
Subs Not Used: Potter, Binns, Nurse.
Sent Off: Deen (22), Oliver (61).
Goals: Morison 16, 31.
Oxford Utd: Turley (Tardif 46), Anaclet, Willmott (Odubade 46), Gilchrist, Johnson, Quinn, Pettefer (Dempster 90), Hargreaves, Day, Burgess, Duffy.Subs Not Used: Slabber, Basham.
Goals: Duffy 54, Hargreaves 59.
Ref: D Cann (Norfolk).