ADAM Smith scored a 96th-minute winner to fire Oxford United into the FA Youth Cup third round.
The match-winner from round one headed home a corner to claim a 4-3 win in an eventful clash at Colchester United which set up a home tie with Maidenhead United.
It is expected the game will be staged at Thame United.
Slavi Spasov (2) and Fabio Lopes also netted against the ten-man hosts, while both sides had a penalty saved.
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Spasov opened the scoring on nine minutes when he converted Tyler Goodrham's pass.
Goalkeeper Max Evans saved a Jake Hutchinson penalty given away by Nico Jones, but the Colchester player equalised just after the half-hour mark.
Andre Hasanally put the hosts in front just after half-time, but Lopes quickly equalised.
The U's forward had a penalty saved, but when another spot kick chance arrived three minutes later Spasov made it 3-2.
Colchester's task got tougher when Marley Marshall-Miranda was sent off, but they equalised again through Diogo Freitas-Gouveia 11 minutes from time.
As extra-time loomed, Smith headed in a stoppage-time corner to ensure United progressed.
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