West Ham were beaten by a talented and disciplined Palermo side in their Uefa Cup first-round, first-leg tie.
Caracciolo celebrates scoring the winner for Palermo
They were caught out when Andrea Caracciolo guided in Aimo Diana's cross, just minutes after Carlos Tevez had missed a similar chance.
Tevez and fellow Argentine Javier Mascherano were making their first starts for West Ham but their obvious influence could not prevent defeat.
Marlon Harewood should have, but he hit the post with a close-range shot.
That was the closest West Ham came to scoring an equaliser which would have been reward for their passionate display.
The Hammers' second-half rally book-ended their performance as they had started the match in similar fashion.
Tevez, who some felt was not as lean as he could be when he made his debut on Sunday, certainly had the appetite to show his class from the kick-off.
Within a few minutes his neat flick and turn bamboozled Mattia Cassani and the Palermo man was booked for his crass intervention.
Later, Tevez showed he could pass as well as compatriot Mascherano, when his clever reverse through ball was inches away from playing Lee Bowyer clean through on goal.
But if West Ham's Argentine contingent were in good form, the rest of their team-mates were not quite playing to the same beat.
Lacking both width and thrust, West Ham's attacks were being easily repelled by their typically astute Italian opponents.
And Palermo should have taken the lead on 18 minutes when Anton Ferdinand was embarrassed by David Di Michele's nutmeg, but the striker then scuffed his shot wide.
West Ham's efforts on goal were limited to a wayward Nigel Reo-Coker shot and a poorly-placed Ferdinand header.
And then Tevez wasted a glorious chance to open his account when he met Bobby Zamora's sublime cross on the volley but steered it too close to Alberto Fontana.
Although it was a good reflex stop by Fontana, a striker of Tevez's ability should have been able to place the ball sufficiently wide of a 39-year-old keeper.
And then West Ham paid the price as a virtually identical attack from Palermo saw Diana deliver an exquisite centre and Caracciolo convert with his knee.
Soon after the break, Paul Konchesky fizzed a free-kick just past the foot of the upright - he had tried a shot from similar distance in the first half, too.
But for all their possession, West Ham lacked the guile to prise open a Palermo backline well practised in the art of resolute Italian defending.
That was until substitute Harewood connected with Yossi Benayoun's cross, but West Ham's hopes of a leveller died as the ball bounced off the woodwork.
West Ham boss Alan Pardew:
"Hitting the post, the save against Carlos Tevez. You need those things to go your way. Against a top-eight team in Serie A, we did okay.
"In terms of what we've seen we have nothing to be frightened of.
"We have not really nailed the team down as we would want and we have to do that now."
West Ham: Carroll, Mears, Gabbidon, Ferdinand, Konchesky, Benayoun, Reo-Coker, Mascherano, Bowyer (Etherington 59), Zamora (Cole 78), Tevez (Harewood 78).
Subs Not Used: Green, Sheringham, Mullins, Collins.
Booked: Reo-Coker, Etherington.
Palermo: Fontana, Cassani, Zaccardo, Barzagli, Pisano, Diana, Parravicini (Guana 54), Simplicio, Di Michele (Capuano 80), Caracciolo, Bresciano (Biava 90).
Subs Not Used: Agliardi, Tedesco, Dellafiore, Brienza.
Booked: Cassani, Pisano, Di Michele.
Goals: Caracciolo 45.
Ref: Stefan Johannesson (Sweden).