The home side were still reflecting upon the eleventh hour collapse of their proposed £6m signing from Porto, the South Africa international forward Benni McCarthy, and the sight of Milan Baros in the Villa line provided another measure of discomfort given that the club had been ready to pay the required fee to take him from Liverpool.
Predictably enough, Pardew emphasised before this match that the circumstances had offered the strikers already at Upton Park the opportunity to re-state their cases.
Harewood's opening 20 minutes offered no hint of what was to come as a couple of inept attempts to control the ball earned him more of the rumbling criticism that had accompanied his recent performances.
But after 24 minutes he took advantage of Olaf Mellberg's slip to start taking his manager at his word, boring in on goal from an inside-left position after Teddy Sheringham's smart forward header and driving home a low shot.
Within five minutes Harewood had demonstrated how vital a factor confidence is to players who are meant to score goals. Matt Etherington's corner offered Anton Ferdinand a free header at the back post. As the ball arrived in the six-yard box Harewood flicked out a languid foot to divert it over his shoulder and past the wrong-footed Villa keeper Thomas Sorensen. It was a classic poacher's goal.
Baros was not the only new signing on show for the visitors, who offered debuts to former PSV Eindhoven right-back Wilfred Bouma, and wide midfielder James Milner, an arrival from Newcastle.
The England Under-21 player offered a glimpse of his talent in the 44th minute as his powerful drive from the edge of the box was tipped round the post by West Ham keeper Roy Carroll. Three minutes after the break Villa should have pulled a goal back when Milner's cross-cum-shot drifted across Carroll and ricocheted off the inside of the far post to the waiting Kevin Phillips, who contrived to smash it back against the woodwork.
Fortune was hiding from the visitors but promptly peeked out at the other end within a minute when Sorensen missed Etherington's cross from the right and Harewood only had to trap the ball and swivel to shoot into an unguarded net for his third goal.
West Ham United (4-4-2): Carroll; Repka, Ferdinand, Gabbidon, Konchesky; Benayoun, Reo-Coker, Mullins (Dailly, 89), Etherington (Newton, 69); Harewood (Zamora, 75), Sheringham. Substitutes not used: Hislop (gk), Aliadière.
Aston Villa (4-4-2): Sorensen; Bouma, Hughes, Mellberg, Barry (Berger, 61); Ridgewell, McCann (Hendrie, 81), Davis, Milner; Phillips (Angel, 57), Baros. Substitutes not used: Taylor (gk), Cahill.
Referee: R Styles (Hampshire).