Aldo stunned Gamburyan with a straight right to the chin and, moments later, connected on a right uppercut that the Armenian-American fighter ducked into.
Gamburyan went to the canvas after the punch and Aldo took his back and then unleashed 10 consecutive strikes, all of them brutal, landing eight right hands to Gamburyan's head before finishing the fight with two lefts as Gamburyan briefly went limp.
Aside from a sizeable mouse under his left eye after the fight, Gamburyan was standing and cognizant shortly after the fight.
Gamburyan (11-5), who trained extensively at Glendale Fighting Club for his training camp and was cornered by GFC's Edmond Tarverdyan and George Bastrmajyan, as well as Team Hayastan's Gokor Chivichyan, hung tough with Aldo (18-1) in the first round, possibly taking it on the scorecards, though it was close.
The two circled each other for most of the round, but Gamburyan came out with a 1-2 combo at the onset of the round that pushed the champion back to the cage.
Left-right combos, whether a jab followed by a hook or an overhand right or consecutive hooks marked Gamburyan's best offense in the stanza. Aldo's best weapon was his vaunted leg kicks, as he landed four in the round, the last of which buckled Gamburyan's left leg and left him limping. Just before the round ended, Gamburyan shot in for a single-leg takedown, but Aldo deftly pulled his leg free.
For the most part, the first round was a feeling-out process with a smattering of jeers from the crowd, as both fighters seemed wary of each other's offense.
Gamburyan came out aggressively with a double-leg attempt at the top of the second round, but Aldo defended it well. Moments later, Aldo landed another crisp leg kick that came just before the aforementioned straight right began the finishing sequence.
It was the 11th straight win for Aldo, considered by most MMA pundits to be among the top-four pound-for-pound fighters in the world. It was also his second straight title defense and eighth consecutive win in the WEC.
"If it's up to me, my reign will last forever," Aldo said.
The loss was the first for Gamburyan in the WEC, ending a three-fight winning streak.