Long was playing for Reading two seasons ago when he scored twice to give them a shock 2-0 half-time lead against Villa in a home FA Cup quarter-final.
But Long's dreams of playing at Wembley in the semi-finals were shattered when Villa hit back to win 4-2.
Long said: "Getting relegated with Reading was a bad day but that Villa cup defeat was up there as one of the biggest disappointments of my career.
"If Reading had won, it would have been the first time they had got to the cup semi-finals.
"At half-time, we were told to go back out and see out the first 15 minutes of the second half at 2-0. Within 10 minutes, we were 3-2 down.
"At least Villa haven't got John Carew now. He was ridiculous up front with his strength and touch that day.
"But I learnt a lot from that game. It showed the sort of club that Villa are and we've got to be right on our game to come away with a result this weekend.
"Hopefully I can emulate the two goals again and put things right.
"But, if we do take the lead, we've got to be as resilient as we were against Wolves at the weekend and see the game out."
Long has warned Albion to expect a backlash after Villa's 4-1 setback at Manchester City last weekend.
He said: "It is going to be tough. It is a hard place to go. Villa have a lot of history there and they are a great side.
"They have started very well but lost 4-1 at City so will come out all guns blazing trying to put that right and prove themselves.
"But, I know if we perform as well as we did against Wolves, we can come away with all three points."
Source: Team Talk