US Marine Corps officer Brian Stann added the WEC light-heavyweight belt to his list of honours and decorations following a title clash on Wednesday night that lasted just 95 seconds.
Reigning champion Doug 'Rhino' Marshall was peppered with leg kicks at the start of the first round and struggled with Stann's superior reach as he attempted to return shots of his own.
However, a subsequent clinch appeared to herald a reversal of Marshall's fortunes as he first tied up his opponent then created enough space to land some combinations.
But Stann was not to be so easily cowed and he blocked and parried, waiting for his opening. When that opening came, he delivered a straight right-left hook combination that left Marshall down and out.
The knockout brought Marshall's considerable run as WEC light-heavyweight champion to an end. He was previously on a seven fight winning streak.
On the undercard, middleweight standout Chael Sonnen won a unanimous decision over Bryan Baker and by doing so kept his title shot hopes alive.
Baker was previously undefeated before taking on Sonnen as a last minute replacement for Paulo Filho, who pulled out of what was to be a title fight with Sonnen, citing substance abuse problems.
Other results from WEC 33 are as follows:
* Marcus Hicks vs. Ed Ratcliff via submission (guillotine choke) Round 1
* Steve Cantwell def. Tim McKenzie via submission (rear-naked choke) Round 1
* Hiromitsu Miura def. Blas Avena via KO (punches) Round 1
* Brock Larson def. John Alessio via DQ (illegal knee) Round 1
* Richard Crunkilton def. Sergio Gomez via unanimous decision
* Alex Serdyukov def. Ryan Stonitsch via submission (triangle choke) Round 1
* Chris Manuel vs. Kenji Osawa via split draw
* Logan Clark def. Scott Harper via TKO (strikes) Round 1