Hammers' lack of cutting edge frustrates Big Sam
West Ham manager Sam Allardyce blamed his side's poor finishing for their shock home defeat to Cardiff.
The Hammers had numerous chances to get off the mark in their opening Championship clash at Upton Park, but instead were hit by a sucker-punch when Kenny Miller grabbed a stoppage-time goal at the other end.
Scott Parker, still with West Ham despite constant speculation linking him with a move back to the Premier League, set the tone when he was sent through on goal, but took a poor touch allowing Anthony Gerrard to get a tackle in.
Frederic Piquionne rattled a post, Peter Whittingham cleared James Tomkins' header off the line and City goalkeeper David Marshall made fine saves from Piquionne, Matt Taylor and Pablo Barrera.
And the Hammers were made to pay for not turning their dominance into goals when former Rangers striker Miller hit a dramatic winner. Substitute Rudy Gestede charged down the wing and pulled the ball back for fellow debutant Miller to lash home
"From our point of view we've mastered the game, created numerous chances and today was one of those days when we were not clinical enough to punish the opposition and then we paid the ultimate price right at the very end," Allardyce said.