Ollie Rowland's retaken penalty in injury-time earned Conference South outfit Eastbourne a replay against League Two side Oxford.
The spot-kick came when Yemi Odubade was fouled by Chris Willmott and, despite netting, Rowland had to score a second time because of encroachment.
The home side began well but looked to be on their way out after Steve Basham's solo strike put Oxford ahead.
Darren Baker nearly headed an equaliser before Rowland's late intervention.
Eastbourne Borough: Hook, Austin, Baker, Warner, Tuck, Cox (Simmonds 55), Atkin (Piper 84), Smart, Ollie Rowland, Ramsay, Marney (Odubade 56).
Subs Not Used: Hemsley, Lightwood.
Booked: Tuck, Baker, Ramsay.
Goals: Ollie Rowland 90 pen.
Oxford Utd: Turley, Ashton, Roget, Willmott, Robinson, Mansell, Quinn, Hargreaves, Bradbury, Basham, Sabin.
Subs Not Used: Tardif, Davies, Stirling, Hughes, E'Beyer.
Booked: Hargreaves, Roget.
Goals: Basham 70.
Ref: M Russell (Hertfordshire).