Graham Potter suffered a painful start to his West Ham reign as Aston Villa's late surge sealed a 2-1 win in the FA Cup third round on Friday.

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 pound 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."

Third tier Wycombe enjoyed a surprise 2-0 win over Championship side Portsmouth in Friday's other third round tie. (AFP)