ALBION'S basement battle at Fulham proved a game too far for their patched-up defence.
A Baggies backline already decimated by injuries, illness and suspension also had to cope with Marek Cech limping off in the 34th minute.
Their cause was not helped when Scott Carson gifted the hosts a half-time lead in the first minute of stoppage time by letting Simon Davies' fierce long-range effort squirm through his hands.
And, for the third straight game, the visitors were made to pay for sloppy marking at set-pieces as Clint Dempsey headed home in the 55th minute and Brede Hangeland nodded a third ten minutes later.
It meant the Cottagers leapfrogged Albion in the table - and it brought to an end a miserable Christmas and New Year spell that has seen Roberto Di Matteo's men suffer five successive defeats.
James Hurst was handed his top-flight debut as the Hawthorns boss was forced to field a makeshift defence.
Regular right-back Gonzalo Jara returned from a one-game ban at centre-half, where he was partnered by full-back rival Gianni Zuiverloon, who made his first Premier League start of the season.
Di Matteo was without key players Jonas Olsson (Achilles), Paul Scharner (illness), Gabriel Tamas (suspension), Pablo Ibanez (hamstring) and Steven Reid (knee).
Within five minutes of kick-off, Zuiverloon and Jara allowed Chris Baird's lofted ball to drop for Diomansy Kamara in the box. The former Baggies striker swivelled and forced a good save from Carson, who clutched the ball at the second attempt.
Three minutes later, Peter Odemwingie broke down the right and drove the ball across the face of goal. Hangeland could only half-clear but there was no Albion midfielder on hand to take advantage from 12 yards.
Odemwingie latched onto Chris Brunt's flick-on from Carson's punt in the 13th minute and the Nigeria hitman forced a save from David Stockdale with a low 20-yard shot that the Cottagers keeper just managed to hold onto to deny Brunt a tap-in.
Five minutes later, the visitors had a golden opportunity to score when Brunt's slide-rule pass put Jerome Thomas in on goal, only for the former Charlton winger to fire straight at Stockdale from the edge of the box, with John Panstsil bearing down on him.
Thomas pounced on Pantsil's mistake on 21 and saw his 18-yard strike deflect off Aaron Hughes and behind for a corner.
The Baggies' best spell of the half then saw Graham Dorrans slide the ball in behind the hosts' defence in the 25th minute - but Brunt just could not stretch far enough to convert from ten yards and Stockdale gathered.
Clint Dempsey got the better of Zuiverloon from Pantsil's left-wing cross on 33 but the Dutch defender recovered to block the USA international's strike from eight yards.
Albion's defensive crisis worsened a minute later as Cech limped off following a challenge by Pantsil and was replaced by former Fulham loanee Nicky Shorey.
Hurst had impressed thus far but was fortunate to get away with a rare mistake from Pantsil's cross on 36 as he headed the ball straight to Davies - but the former Wales international volleyed well wide from 15 yards.
Moments later, at the other end, Dorrans tried his luck from 35 yards and saw his dipping effort fly just over.
The ball broke to Damien Duff from Hurst's challenge with Davies on 40 and the Republic of Ireland ace saw his 18-yard shot deflect off Jara and fly just wide of the left-hand post.
From the resultant Danny Murphy corner, Hangeland looked certain to score but sent his header inches wide of the left-hand upright from close range, getting an accidental clout on the head from Carson to boot as the keeper mistimed his attempted punched clearance.
Albion's injury-hit defence had coped admirably and looked comfortable after seeing off the Cottagers' early storm.
But all that hard work was undone when Carson gifted Fulham a half-time lead by palming Davies' 30-yard swerving strike into the net in the first minute of stoppage time.
Nine minutes into the second half, Duff managed to wriggle free of Shorey and sent a 20-yard right-footed drive a whisker wide of the left-hand post.
Just a minute later, Mark Hughes' men did double their lead when Dempsey powered home Murphy's left-wing corner from six yards with a textbook header.
The hosts looked like adding a third on the hour-mark but Kamara's return pass to Dempsey gave his strike partner no chance to control the ball as he looked to burst into the box.
Both teams made a change two minutes later as Marc-Antoine Fortuné came on for Youssouf Mulumbu as Albion switched to a 4-4-2 formation, and ex-Baggie Zoltan Gera replaced Kamara.
But it got worse for the visitors, who fell asleep from a Davies corner on 65 and Hangeland was left in acres of space to nod home from close range.
Hurst was unlucky not to pull one back for the visitors on 72 when his goalbound shot was headed away by Murphy.
Seconds later, Odemwingie teed up Thomas, who curled a right-footed shot just wide of the far post.
Etuhu blazed over from 15 yards in the 83rd minute and at the opposite end the Baggies could not force a consolation as Dorrans' 20-yard volley flew just wide.
Odemwingie forced Stockdale into one final save in the 88th minute as he parried the ball out for a corner.
FULHAM (4-4-2): Stockdale; Pantsil, Hangeland, Hughes, Baird; Davies (Riise 82), Murphy, Etuhu, Duff; Dempsey (E Johnson 87), Kamara (Gera 62). Subs not used: Etheridge (gk), Salcido, Greening, Halliche.
ALBION (4-2-3-1): Carson; Hurst, Zuiverloon, Jara, Cech (Shorey 34); Mulumbu (Fortuné 62), Dorrans; Morrison (Cox 69), Brunt, Thomas; Odemwingie. Subs not used: Myhill (gk), Meite, Miller, Tchoyi.
GOALS: FULHAM - Davies (45+1), Dempsey (55), Hangeland (65).
BOOKINGS: ALBION - Odemwingie (foul 89).
REFREE: M Atkinson (Yorkshire).
ALBION STARMAN: Graham Dorrans.
PIC: TOUGH NIGHT...Brunt holds off Etuhu