The Grecians survived a red card for veteran striker Jamie Cureton and a missed penalty by Wycombe's Joel Grant to scrap their way to an eighth away win.
Exeter were reduced to ten men five minutes before half time when Cureton was shown a red card for needlessly kicking out at Anthony Stewart.
The hosts should have went ahead after 53 minutes when Grant was hauled down in the box by Steve Tully but the winger's weak penalty was comfortably kept out by Artur Krysiak.
Alan Gow then almost gave the Grecians the lead against the run of play when his half-volley from just outside the box dipped just over the crossbar.
The visitors grew in confidence however, and snatched the points with eight minutes left when Jordan Archer kept out John O'Flynn's shot only for 17-year-old defender Kortney Hause to dribble into his own net.