ALBION suffered a harsh third successive league defeat after being floored by two Norwich sucker-punches.
Sub Shane Long's 50th career league goal, which he converted from the spot in the 68th minute, looked to have earned the Baggies a point.
And that would have been the least they deserved after dominating large parts of the game.
But Steve Morison had the final say, converting a Canaries counter-attack 11 minutes from time.
It was a similar story in the first half, with Roy Hodgson's men putting the visitors' goal under concerted pressure, only to fall behind to Andrew Surman's 43rd-minute breakaway goal.
Ninth-placed Norwich started the day some six places, but only three points, better off than the Baggies in a congested mid-table.
Albion were boosted by the return of fit-again trio Youssouf Mulumbu, Paul Scharner and Jerome Thomas to the starting XI, while Long made the bench.
The men to make way were the injured Billy Jones (thigh) and benched duo Graham Dorrans and George Thorne.
Simon Cox's FA Cup hat-trick against Cardiff seven days ago earned him a second successive start - but it was strike partner Peter Odemwingie who almost broke the deadlock in the fifth minute.
The Nigeria striker collected a loose ball 30 yards out and saw his ferocious effort brilliantly tipped onto the crossbar by John Ruddy.
With neither team intent on sitting back, it made for a lively opening and Norwich went close themselves on 12.
Ben Foster raced off his line to prevent Morison getting on the end of a loose ball in the box but the Albion No.1's clearance ricocheted off the Canaries striker's boot and drifted back towards the gaping goal. Thankfully for the hosts, the ball hit the outside of the post and slid out for a goal-kick.
Moments later, Cox and James Morrison combined well to set up a half chance for Odemwingie, who blazed wide of the near post from just inside the penalty area.
Norwich threatened next when Simeon Jackson fired harmlessly over from Anthony Pilkington's centre.
But it was Albion who were creating the better chances and Cox was denied at point-blank range on 21 after more great link-up play by Odemwingie and Morrison had put him in the clear.
Another fine Baggies move led to the hosts having loud penalty appeals turned away on 27 when Thomas appeared to be tripped just inside the box by Daniel Ayala. TV replays suggested referee Mike Dean got it right.
The Albion pressure continued but Odemwingie was unable to direct the ball goalwards after Paul Scharner had headed Morrison's corner into the danger-zone.
Seconds later, there was more Albion agony when Morrison saw his stunning half-volley from just inside the box headed off the line by Surman.
Norwich were hanging on for dear life and Thomas saw a goalbound effort brilliantly blocked by Zak Whitbread after Odemwingie and Cox had scythed open the visitors' defence.
City didn't get close to the Baggies goal again until the 38th minute, when Morison headed weakly wide from Pilkington's left-wing centre.
However, completely against the run of play, Paul Lambert's team broke the deadlock on 43.
Jackson spearheaded a counter-attack by chasing down a long ball before teeing up Wes Hoolahan, whose centre was superbly volleyed home by Surman from 15 yards.
Albion had dominated the first half but somehow found themselves 1-0 down at the break.
The Baggies created their first shooting chance of the second half in the 49th minute, when Morrison's 20-yarder rose over the bar from Odemwingie's lay-off.
Moments later, Scharner chose to shoot from the edge of the box, when it would have been wiser to cross to a team-mate, and miscued well wide.
Morrison was having a fine game and went close again on 55 when he saw a 25-yard volley land agonisingly on the roof of the net after Cox had headed back Gonzalo Jara Reyes' angled ball.
Albion were well on top again and Norwich didn't record their next shot at goal until the 57th minute, when Jackson shot straight at Foster from just inside the box.
However, the Baggies began to lose their zip and Hodgson made a double change on 63, bringing on Long and Dorrans for Odemwingie and Scharner.
Long almost levelled within seconds, swivelling smartly from Thomas' dink into the box and seeing his snapshot brilliantly kept out by Ruddy. Cox turned the loose ball goalwards but Whitbread cleared off the line.
Moments later, Long teed up Cox and his powerful 18-yarder flew straight at Ruddy, who gathered at the second attempt.
But Albion were thrown a deserved lifeline on 68 when Ayala hacked down Thomas in the box and conceded a penalty. Long made no mistake, coolly sending Ruddy the wrong way from 12 yards for his sixth goal of the season
Norwich regrouped but Morison was well off target with a header from Surman's corner on 73.
The game was now delicately poised and it was Albion who attacked next, with Long flashing a header well wide from Jara Reyes' centre.
Craig Dawson then planted a firm header straight at Ruddy from Dorrans' centre.
But Albion were hit by another sucker punch.
In the 79th minute, Youssouf Mulumbu conceded possession on the edge of the Norwich box and the Canaries launched another swift counter-attack, which culminated in Morison heading home sub Grant Holt's centre at the back post.
Albion huffed and puffed during the closing stages but were unable to carve out a deserved leveller.
ALBION (4-4-2): Foster; Jara Reyes, McAuley, Dawson, Shorey (c); Morrison, Mulumbu, Scharner (Dorrans 63), Thomas (Fortune 77); Cox, Odemwingie (Long 63). Subs not used: Fulop (gk), Thorne, Mattock, Tamas.
NORWICH (4-4-2): Ruddy; R Martin, Ayala, Whitbread, Naughton; Pilkington (Crofts 68), Johnson (Fox 80), Hoolahan (c) Surman; Morison, Jackson (Holt 68). Subs not used: Steer (gk), Drury, Bennett, Wilbraham.
GOALS: ALBION - Long (pen 68). NORWICH - Surman (43), Morison (79).
BOOKINGS: NORWICH - Ayala (foul 67).
REFEREE: M Dean (Wirral)
ALBION STARMAN: James Morrison.