Brendan Rodgers’s side had lost 1-0 at home to Aston Villa the previous weekend before marking their Champions League return with a 2-1 success against Bulgarian club Ludogorets in midweek.
Poor defence, their Achilles heel when finishing runners-up to champions Manchester City in last season’s Premier League, cost Liverpool dear at Upton Park where West Ham were 2-0 up inside seven minutes.
Although Liverpool were the better side for almost an hour after that, a late goal by home substitute Morgan Amalfitano made sure there was no comeback for the Merseysiders’ travelling supporters to celebrate in east London.
Rodgers handed Italian forward Fabio Borini a first start since January last year and the first in the Premier League since September 2012.
West Ham manager Sam Allardyce started with Alex Song for the first time, the former Arsenal midfielder having been borrowed from Barcelona for the season.
There was an extraordinary start to the game as the home side took the lead after just 77 seconds.
James Tomkins out-jumped Jordan Henderson at the far post from Stewart Downing’s free-kick and Winston Reid was there to head in off Liverpool defender Dejan Lovren.
Reid was then booked for a foul on Borini before West Ham made it 2-0 in the seventh minute.
Mark Noble’s ball found Diafra Sakho in space on the right of the box and the Senegal striker floated what appeared to be a cross over Liverpool goalkeeper Simon Mignolet and into the net.
Enner Valencia, another new recruit, came rushing in to make sure but the ball was already over the line but the goal belonged to Sakho.
– Toiling Liverpool –
Liverpool continued to toil and Mignolet had to tip a long-range shot from Aaron Cresswell round a post before Mario Balotelli became the centre of attention at the other end.
The Italy forward went in late on West Ham goalkeeper Adrian, who reacted angrily, and referee Craig Pawson ended up booking both men.
Rodgers made a tactical change after just 22 minutes, switching to three at the back by replacing Javier Manquillo with Mamadou Sakho.
It worked as Raheem Sterling smashed in a reply in the 26th minute after Balotelli had seen a shot charged down.
There were more problems for Liverpool however when Lovren was hurt in a clash with Mamadou Sakho, his team-mate, but the Croat was able to carry on with a bandage round his head.
Liverpool made another change at half-time, with Adam Lallana replacing the anonymous Lucas.
Sterling fired wide before Borini forced Adrian into a save as the visitors began to look more menacing, with Balotelli next to see an effort saved.
Liverpool had the momentum, with the speedy Sterling the biggest threat, and Allardyce made changes, bringing off Guy Demel and then Song for Carl Jenkinson and Amalfitano respectively.
Rodgers introduced England forward Rickie Lambert in place of Borini for the final 15 minutes and the Hammers sent on an extra defender in James Collins, who replaced Valencia.
Liverpool’s hopes of a point ended in the 88th minute when Downing, a former Anfield player, threaded a through-ball to Amalfitano, who poked a shot past Mignolet and into the far corner to cue frenzied celebrations from the home fans.