West Ham inflicted Liverpool's first defeat of the season to knock the visitors off the top spot in a passionate clash at Upton Park.
John Hartson opened the scoring after four minutes with his second of the season courtesy of some generous Liverpool defending that allowed him a free header.
Israeli international Eyal Berkovic added the vital second in the 50th minute with a powerful drive past the unsighted Brad Friedel.
And the Hammers hung on for all three points despite substitute Karlheinz Riedle's 88th minute consolation that raised hopes of a Wimbledon-style comeback.
Liverpool enjoyed plenty of possession but lacked the killer touch in a formation that had Michael Owen too often isolated up front until the introduction of Riedle.
And it took just four minutes for Liverpool's Achilles heel of defending at crosses to resurface as Hartson of all people was allowed a free header to open the scoring.
Lampard's corner should have been cleared before it reached Hartson but when it did he made no mistake, heading home from six yards with Friedel getting a hand to it but unable top prevent the ball crossing the line.
The crowd sat back and expected another first half like Wednesday night but despite the majority of the chances the goals never came for the home side.
Skipper Ian Wright was booked for a late foul on Vegard Heggem before Hartson almost doubled the lead after 15 minutes had gone.
The Welsh international appeared to have dithered too long on the ball in front of the area but found Trevor Sinclair wide in space on the left with a delightful chip.
Sinclair returned the favour with a cross to the far post but the angle was too narrow and Hartson headed just wide.
Ian Pearce unfortunately had no such excuses when he wasted the best chance of the half after 26 minutes. Again a Lampard corner was met by Hartson whose header was half blocked. It fell perfectly for Pearce on the half volley but with the goal beckoning the former Blackburn defender blazed his shot wildly over the bar.
West Ham were lucky not to be made to regret their profligacy as Liverpool gradually began to assert themselves and go in search of an equaliser. Michael Owen went close with one shot over the bar after a fine run before Ince wasted a good chance to level the scores. The skipper looked to have a free header from Steve Staunton's corner but failed to make proper contact and Shaka Hislop saved comfortably.
Harkness was then booked for a foul on Wright before McManaman volleyed straight at the keeper when given time to bring down Berger's cross.
Liverpool were almost caught cold after the break when within seconds of the restart Berkovic threaded a superb ball through to Hartson. He looked certain to score before Babb did just enough to knock him out of his stride to allow Friedel to come out and block and the danger was cleared.
But the home crowd only had to wait another four minutes before Berkovic himself increased the lead.
This time Hartson was the provider, setting up Berkovic to fire past Friedel from the edge of the box with the keeper looking partially unsighted by defenders in front of him.
That forced Liverpool to chase the game - Riedle coming on for Harkness - and the German almost had an instant impact, heading down well only for McManaman to drag his shot wide. The game at times threatened to boil over and Ince was lucky to get away with a two-footed challenge on John Moncur after 64 minutes.
Three minutes later Redknapp thought he had pulled a goal back with a superb free kick only to see Hislop fling himself away down low to his right and pull off a brilliant save.
The visitors finally reduced the deficit on 88 minutes, Riedle, who had earlier hit the post, heading home substitute Jason McAteer's superb cross but it clearly wasn't going to be Liverpool's day.
Even Owen was proved to be fallible, tripping over his own boots as the league leaders tripped up on their travels.
West Ham: Hislop, Potts, Ruddock, Sinclair, Hartson (Keller 86), Wright, Moncur, Lazaridis, Lampard, Pearce, Berkovic (Breacker 88).
Subs Not Used: Forrest, Impey, Abou.
Booked: Wright, Hartson, Moncur, Lazaridis, Sinclair.
Goals: Hartson 4, Berkovic 51.
Liverpool: Friedel, Staunton (Matteo 62), Babb, McManaman, Owen, Redknapp, Harkness (Riedle 54), Heggem (McAteer 72), Berger, Ince, Carragher.
Subs Not Used: James, Kvarme.
Booked: Harkness, Redknapp.
Copyright - Press Association