Two goals from Chris Dagnall helped Leyton Orient knock holders Peterborough out of the Johnstone's Paint Trophy following a 3-2 win at London Road.
Dagnall scored early in both halves with Marcus Maddison equalising in between.
Bradley Pritchard's clever flick on the hour sealed the win for Orient, who played over 20 minutes with 10 men when Romain Vincelot was sent off, before Posh debutant Luke James scored a late consolation.
Orient took the lead in the fourth minute when Lloyd James' free-kick from the right was headed in by an unmarked Dagnall but Maddison equalised after 16 minutes with a driven 20-yard shot after a quick corner.
Orient regained the lead two minutes into the second half when Dagnall, running down the left side of the area, smashed in James' through-ball at the near post.
Pritchard flicked in Dagnall's right-wing cross after 62 minutes, although Vincelot received a second yellow card soon after for a trip on Maddison.
James tapped into an empty net in injury time but it was too late.