The Power secured a 12th straight victory in extraordinary circumstances, with utility Houston roosting his kick from outside the 50m arc on a tricky angle.
Port players were confident the ball had carried over the goal-line, but a score review was taken to be sure.
The AFL Review Centre made a quick decision, with replays showing the ball clearly having the distance as Port prevailed 11.12 (78) to 10.14 (74) on Saturday.
In a rollercoaster final quarter, Essendon took a nine-point buffer into the last term, but the Power's star-studded midfield kicked into gear.
Midfield stars and Brownlow Medal contenders Zak Butters and Connor Rozee kicked crucial fourth-quarter goals to push Port out to a 16-point lead.
But the resilient Bombers came again, with Jye Caldwell and Kyle Langford goaling in quick succession.
Caldwell marked with 90 seconds remaining, slotting the goal to put Essendon back in front.
Darcy Parish snapped to seal the result for the Bombers but his shot went wide to give Port a chance of pinching it from the kick-in.
In a frantic final minute, Nic Martin attempted to clear the ball out of Port's forward-50 but the kick was marked by Houston.
The 26-year-old was the leading possession winner on the ground with 32 while Kane Farrell, Butters and Rozee were all damaging for Port.
Port's ruck plans were thrown into chaos just minutes before the bounce when Scott Lycett failed a fitness test.
Lycett's injury opened a position for Dante Visentini to make his AFL debut in exceptional circumstances, pulled out of the emergencies and was not even warmed up when the game started.
Forward Jeremy Finlayson was forced to take on a bigger load than normal in the ruck with Visentini battling hard, just without experience.
It allowed Essendon's Andrew Phillips to take control in the ruck as the Bombers' midfielders lifted after quarter-time when Port led the clearances 7-1 at the first change.
Visentini was substituted out at the start of the final quarter for Jase Burgoyne as Port chased more running power.
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