Potter makes losing start as Villa knock West Ham out of FA Cup
Potter was hired by the Hammers on Thursday to replace Julen Lopetegui, who was sacked earlier this week after just six months in charge.
But the former Chelsea manager was unable to make a winning return to the dug-out as West Ham squandered the first half lead given to them by Lucas Paqueta.
On a freezing evening at Villa Park, Unai Emery's men emphasised the size of the task facing Potter with a second half fightback that exposed West Ham's defensive flaws.
Amadou Onana equalised before Morgan Rogers bagged the winner to leave Potter holding his head in frustration.
The former Brighton boss is back in management for the first time since being dismissed by Chelsea in April 2023.
Potter lasted less than seven months at Chelsea, losing 11 times in his 31 games in charge and slumping to 11th place in the top-flight despite a £288 million ($351 million) spending spree in his one transfer window.
Potter has tried to learn from the "pain" of that failure, vowing to "come back stronger" after an experience that may have cost him a chance at the England job when Thomas Tuchel was hired last year.
Potter had just one training session with his players before the trip to Villa and was without key forwards Jarrod Bowen and Michail Antonio.
Under the circumstances, he can be encouraged by West Ham's attacking play but fixing their issues at the back must be top of his to-do list.
"Overall, disappointed to go out, but lots of positives in the game," Potter said.
"The start was really good but in the second half Aston Villa stepped-up and pushed us back a bit too much. That's something we will have to improve."
Lopetegui was unable to build on the solid foundations left by David Moyes, who won the Europa Conference League in 2023 before stepping down at the end of last season amid fan complaints about his dour style of play.
Potter certainly looks capable of banishing those concerns as West Ham attacked Villa with verve in the first half.
Paqueta was close to giving Potter a dream start when the Brazilian's strike from the edge of the area flashed just wide.
It was a warning Villa failed to heed as Paqueta opened the scoring in the ninth minute.
Crysencio Summerville teased Villa's Ian Maatsen with an incisive run into the area before slipping a pass to Paqueta, who planted a clinical finish past Robin Olsen.
Potter celebrated in fist-pumping style but there was a setback for the new manager when Germany striker Niclas Fullkrug limped off soon after the goal.
Paqueta was a constant threat and he forced Olsen to save after another menacing raid.
But Villa's second half surge was rewarded in the 71st minute.
Tyrone Mings flicked on a corner to Maatsen and Fabianski could only push his shot to Amadou Onana, who reacted quickest to poke home from close-range.
West Ham were furious, claiming the corner should not have been awarded because Boubacar Kamara's shot was not deflected.
But Villa scented blood and went for the kill in the 76th minute.
Ollie Watkins burst into the West Ham area and pulled his pass back to Rogers for a clinical strike into the bottom corner.
Third tier Wycombe enjoyed a surprise 2-0 win over Championship side Portsmouth in Friday's other third round tie.