Meanwhile, West Ham slumped to their third straight league defeat as they failed to consistently threaten Scott Carson in the Villa goal.
West Ham had the ball in the back of the net, but Henri Camara's effort was disallowed for a blatant handball and this was to be as close as they came.
Villa then struck on 24 minutes when Gardner blasted home a free-kick from 18 yards, which took a late deflection off Daniel Gabbidon to deceive Robert Green in the Hammers goal.
West Ham then enjoyed the majority of possession and were unfortunate not to be awarded a second half penalty when Zat Knight hauled down Carlton Cole in the 18-yard box, but they looked blunt in attack and failed to muster an equaliser.
The pace of Ashley Young caused problems for the Hammers down the left flank and he must have impressed watching England coach Steve McClaren.
Another member of McClaren's latest England squad, Dean Ashton, had a quiet afternoon and picked up a knee injury which could rule him out of the forthcoming Euro 2008 qualifiers with Estonia and Russia.
The first decent opening fell to the home side after five minutes when Young turned past Gabbidon and sent over an inviting low cross, but Luke Moore failed to connect with a volley.
Green was called into meaningful action for the first time when he parried a low drive from Moore after good play by skipper Gareth Barry.
The home side then looked to have strong claims for a penalty after 13 minutes when Lucas Neill appeared to tug at the shirt of Young as he burst into the Hammers box, but it was turned down by referee Steve Tanner.
It was no surprise when Gardner struck for the second time in five days to put Villa ahead after Agbonlahor was brought down right on the edge of the Hammers box by Gabbidon.
West Ham tried to retaliate and Freddie Ljungberg ran at full tilt to meet a deep centre by Matthew Etherington but his flying header was well saved by Carson who was perfectly positioned.
Villa looked dangerous every time the likes of Young and Agbonlahor ran at the West Ham defence.
The visitors were forced to make a substitution when Camara limped out of the action with a hamstring problem to be replaced by Cole.
Villa were soon back on the offensive as they attacked a packed Holte End in the second half and Agbonlahor had a header blocked by Matthew Upson from Young's cross.
Villa, though, almost gifted West Ham an equaliser after 55 minutes when a poor clearing header by Mellberg went straight to Cole just outside the six-yard box, but he failed to make proper contact and Carson was able to save.
The pace of Villa's game had dropped considerably compared to the opening 45 minutes and O'Neill brought on Shaun Maloney for Moore.
Young appealed in vain for a penalty when Neill appeared to deflect his cross past the post via his right arm.
However, Villa comfortably held on to secure the points and move up to fifth in the league.







