Quincy Owusu-Abeyie scored on his Birmingham debut as Wycombe were thrashed 4-0 in the Carling Cup first round at Adams Park.
Mehdi Nafti opened the scoring for the Blues in the 14th minute with his first goal for the club since joining in January 2005.
The midfielder was teed up by Garry O'Connor and his 20-yard drive flew across Jamie Young in the Chairboys goal and into the bottom corner.
Wycombe striker Scott McGleish was denied by Colin Doyle after 57 minutes but Birmingham moved up a gear in the final half hour.
In the 64th minute Sebastian Larsson added a second after being set free by the lively O'Connor.
The Swede then turned provider after 73 minutes when he crossed for substitute Cameron Jerome to head home the third.
Owusu-Abeyie then gave taway fans a taste of things to come with the goal of the game in the 86th minute.