Barry Bannan and Tobias Mikaelsson grabbed goals in the last five minutes as the home side showed just why they're top of the table.
West Ham had opened the scoring inside just 39 seconds as summer signing Julian Faubert finished neatly.
Stuart Taylor started in goal for Kevin MacDonald's men but he was powerless to stop the Frenchman slotting in.
After the goal it was all Villa.
Former England keeper Richard Wright was in fne form for the Hammers as he denied O'Halloran and Harewood.
Both Marlon Harewood and Eric Lund went close as the real Claret and Blue went in search of the equaliser.
Lund hit the post and Harewood missed a one on one as Villa pressed.
The break did nothing to change the pattern of the game as the Villans came out with the same hunger and desire as they showed in the first half.
Harewood again spurned a guilt edged opportunity as Wright presented him with the perfect chance to level. The former Hammers frontman declined the invitation as the ball dropped at his feet following poor handling from the keeper.
Harewood desperately needs a goal to help him rediscover the confidence which could get him into the first team picture. As it stands the striker is more likely to be on his way out of Villa Park rather than on the coach to it.
He again missed a great chance on 71 and that was the final straw as he was replaced by Bannan.
The young Scot almost made an immediate impact, but Wright again saved well.
The home side finally made their inexhaustible pressure tell and Bannan was the man to make the breakthrough.
He found the net with a great left footed strike on 87 minutes and the goal proved to be like a London bus.
Villa had waited all game for one and then two came along at once as Mikaelsson scored the winner just as the match neared its end.
The striker is proving to be prolific in the reserve league this season and it may be he, not Marlon Harewood, who finds himself on the coach to Villa Park.
Make no mistake, this was a good West Ham line-up, but Villa showed just why they are the supreme Claret and Blue and they thoroughly deserved the hard earned victory.
Villa:
Taylor
Lund
Earls
Clark
O'Halloran
Herd
Salifou
Hogg
Hofbauer (Delfouneso 63)
Harewood (Bannan 74)
Mikaelsson
Subs not usedL
Bevan GK
D Bellon
Y Bellon