AWAY-DAY specialist Graham Dorrans' deadly double saw Albion overcome nine-man Scunthorpe in a testing encounter at Glanford Park.
The Scotland international opened the scoring in the 19th minute with a thunderous volley but Rob Jones drew the hosts level within 50 seconds of the second half starting.
The Iron were reduced to ten men in the 61st minute when Andrew Wright was sent-off by referee Jon Moss for a second bookable offence.
And the Baggies took just four minutes to capitalise as Dorrans won and converted a penalty - his fourth goal in as many games on the road - to restore the visitors' lead.
United were forced to play the final 15 minutes with nine men when Grant McCann was red carded for dissent after Luke Moore had won, and Dorrans missed, another spot-kick.
And Gianni Zuiverloon sealed a deserved Albion win with a third goal in the 86th minute.
Roberto Di Matteo made one enforced change as Marek Cech stepped in at left-back with Joe Mattock serving a one-match ban.
The Baggies threatened within the opening 45 seconds as Jerome Thomas skipped inside Marcus Williams from the left before forcing ex-Albion keeper Joe Murphy into a smart save low at his near post.
Four minutes later, Thomas saw another effort saved by Murphy after Dorrans had laid the ball back to him on the edge of the box.
Albion had simply stormed out of the blocks - but it was the hosts who should have been ahead in the eighth minute.
Paul Hayes cleverly flicked a long punt into the path of Garry Thompson who, with only Dean Kiely to beat, dragged his shot wide of the left-hand post.
Seconds later, Thompson crossed from the right and a mix-up between Kiely and Abdoulaye Meite almost saw the ball break for Hayes before Kiely pounced to gather.
The Baggies soon missed a golden chance of their own.
Thomas' left-wing centre just evaded Moore before the ball fell to Chris Brunt who fired into the side-netting when, at the very least, he should have hit the target.
The visitors thought they had broken the deadlock in the 16th minute when Moore raced onto Brunt's ball and battled past David Mirfin, Rob Jones and Murphy to stick the ball in the net, only for referee Moss to disallow the goal after his assistant flagged for a foul.
Moments later, Andrew Wright crossed to the back post where Thompson looped a header over.
But Albion did open the scoring in the 19th minute when Murphy could only punch Cech's left-wing cross to Dorrans and the Scotland international wasted no time in blasting home a left-foot strike from 15 yards.
Two minutes later, Thomas slipped Moore through and he saw his goalbound shot blocked by Mirfin's last-ditch challenge.
Williams looped over a back-post cross in the 25th minute and Michael O'Connor saw a spectacular scissor kick fly wide from 15 yards.
Simon Cox flicked on Zuiverloon's throw-in in the 36th minute and Brunt looked set for a strike on goal before losing his footing in the icy penalty area.
Two minutes later, the Northern Ireland international tried his luck from outside the box and saw a skidding effort whizz inches past the right-hand post.
Albion finished the half well in control but were pegged back within 50 seconds of the restart when O'Connor's cross from a short corner was deflected goalwards.
Kiely could only parry the ball and ex-Hibernian defender Jones headed home from close range.
Another short corner in the 50th minute gave O'Connor the chance to shoot and he drilled a 20-yard effort just past the left-hand angle of post and bar.
Handling was proving difficult in the icy conditions and Kiely did well to hold onto Sam Togwell's header from McCann's curling ball into the box in the 53rd minute.
Scunthorpe were a transformed outfit during the opening stages of the second 45 but Albion dug in and eventually got back on top.
Dorrans burst forward in the 58th minute and fired in a low cross from the right which Cox dummied for Moore and he fired straight at Murphy from six yards as Andrew Wright challenged him.
Thomas looked like bursting through on goal in the 61st minute but was felled by Andrew Wright and he was given his marching orders for a second bookable offence.
From the resulting free-kick, Dorrans lofted the ball in and Moore headed home - only for the striker to have a SECOND 'goal' ruled out - this time for offside.
But Albion didn't have to wait long to get back in front.
The lively Dorrans was tripped by Jones in the box in the 65th minute and the Scotland ace picked himself up to slot home the spot-kick, despite Murphy getting a touch on the ball.
Scunthorpe could have levelled in the 68th minute but sub Martyn Woolford headed straight into Kiely's arms from McCann's left-wing cross.
Sub Chris Wood did well to break to the right byline in the 75th minute and cut the ball back for Moore, who was flattened by Mirfin to earn another penalty.
And McCann was then sent-off for dissent by West Yorkshire official Moss as he complained about the decision.
Dorrans stepped up to take the spot-kick but saw his hat-trick chance saved low to his right by Murphy.
Albion made the most of their two-man advantage during the dying stages by keeping the ball for long spells.
Murphy had to swoop low to his right in the 83rd minute to tip Zuiverloon's stunning 20-yard drive around the post.
Two minutes later, Murphy did well again to keep out Moore's 20-yard strike.
But Albion weren't to be denied a third goal, which reflected their superiority.
Four minutes from time, Zuiverloon broke into the box and lashed Brunt's square ball home from 15 yards to secure the three points.
SCUNTHORPE (4-5-1): Murphy; Williams, Mirfin, Jones, A Wright; McCann, O'Connor, Togwell, J Wright (Woolford 54, May 88)), Thompson (Forte 83); Hayes. Subs not used: Slocombe (gk), Sparrow, Spence, Canavan.
ALBION (4-4-2): Kiely; Zuiverloon, Meite, Olsson, Cech; Brunt (Martis 88), Jara, Dorrans (Mulumbu 78), Thomas; Moore, Cox (Wood 63). Subs not used: Allsop (gk), Bednar, Teixeira, Reid.
GOALS: SCUNTHORPE - Jones (46). ALBION - Dorrans (19, 65 pen), Zuiverloon (86).
BOOKINGS: SCUNTHORPE - A Wright (foul 37), Murphy (dissent 65). ALBION - Thomas (foul 50), Jara (foul 76)
SENDINGS-OFF: SCUNTHORPE - A Wright (second bookable offence 61), McCann (dissent 75).
REFEREE: J Moss (West Yorkshire).
ATTENDANCE: 7,221 (1,600 approx Albion fans).
ALBION STARMAN: Graham Dorrans.
PIC: GREAT SCOT...Cech and Thomas congratulate Dorrans after his fine opening goal