Pompey have sold their full allocation of tickets for the league visit to Oxford.
Kenny Jackett's side visit the Kassam Stadium on Saturday, January 19 (3pm kick-off).
And they will be backed by 1,800 Blues fans, with every seat snapped up within 40 minutes of going on sale to season ticket holders and shareholders this morning.
Supporters who have bought concession tickets are advised to bring proof of age identification with them to the game.
Official coach travel can be booked online here or by calling Lucketts Travel on 01329 237000.