Cameron Brannagan scored the winning penalty as Oxford reached the English League One play-off final with a 5-4 shootout win over Portsmouth.
The hosts converted all of their spot-kicks in a dramatic finale as Karl Robinson's side booked a place against Wycombe who drew 2-2 with Joey Barton's Fleetwood Town but won 6-3 on aggregate, at Wembley next Monday.
Barnsley loanee Cameron McGeehan saw his penalty superbly saved by Oxford goalkeeper Simon Eastwood as Portsmouth's play-off woes continued, having now never made the finals in four attempts.
Wycombe. who were tipped to be relegated at the start of the season, will be looking to reach the second tier of the English game for the first time in their history.
Fleetwood, who lost the first leg at home 4-1, gave themselves a glimmer of hope when Danny Andrew struck in the first half.
A dreadful defensive error by Socceroos centre-back Harry Souttar gifted Wycombe an equaliser for Fred Onyedinma.
Ched Evans restored the visitors' lead from the penalty spot before Onyedinma grabbed his second with a superb finish in the final minute.
Australian Associated Press
