SUB Victor Moses' 70th-minute strike snatched Wigan the points from the tightest of encounters at the DW Stadium.
The match looked to be heading towards a goalless stalemate until the Latics' half-time replacement fired the only goal of the game.
The teams cancelled each other out in a match of few chances, with both goalkeepers having little to do.
Buoyed by a nigh-on 4,000-strong travelling support, Roberto Di Matteo's troops once again refused to throw in the towel but struggled to find a way in behind the hosts' defence to suffer a third narrow defeat in four games.
Nicky Shorey shook off an ankle injury and Youssouf Mulumbu returned from suspension as Di Matteo made two changes to his starting XI.
The men to make way were benched duo Marek Cech and Graham Dorrans.
The hosts were first to threaten in the third minute when Ronnie Stam flung over a back-post cross and Tom Cleverley fired the ball back across goal, where Pablo Ibanez denied Hugo Rodallega a tap-in.
A minute later, Rodallega broke past Mulumbu and Gabriel Tamas into the box and squared for Charles N'Zogbia, whose poor first touch allowed Scott Carson to gather the ball.
The Latics were forced into a change in the 17th minute as the injured Gary Caldwell made way for his brother Steven at centre-half.
Tamas' first-time ball set Peter Odemwingie free in the 26th minute and he beat Antolin Alcaraz to get to the byline, only to find there was no team-mate in support as he cut the ball back.
Moments later, the Nigeria international exchanged a one-two with James Morrison on the edge of the area before drilling a shot just wide of the right-hand post.
N'Zogbia switched from the right to the left flank midway through the half and on 35 he beat Steven Reid before firing in a cross that Ibanez did well to divert into the side-netting.
From the resultant N'Zogbia corner, Alcaraz, under pressure from Tamas, sent his free header well wide from 15 yards.
Three minutes before the break, Paul Scharner, on his first return to Wigan, flicked on Reid's throw-in from the right and Morrison saw his 12-yard volley deflect off Cleverley and fly just past the right-hand post.
Scharner threw himself at Brunt's ensuing corner but just failed to make telling contact in the six-yard box.
The Baggies' spell of pressure continued as the half drew to a close.
And the Latics defence had to make important blocks in their own penalty area to deny Reid and Scharner.
Wigan started the second half brightly and within the opening two minutes Reid needed to be alert to prevent Rodallega getting on the end of N'Zogbia's ball into the box.
Half-time sub Moses raced to the right byline in the 50th minute but his low cross evaded both N'Zogbia and Rodallega.
Thomas' persistence saw him dispossess Latics right-back Stam and the ball broke for Odemwingie, who cut inside before being fouled by Caldwell inches outside the penalty area.
Brunt managed to wriggle free of Steve Gohouri on 59 but saw his low 25-yard drive comfortably saved by Ali Al Habsi at the foot of his left-hand upright.
Morrison tricked his way past Caldwell on the edge of the box a minute later and fired in a shot that Al Habsi just held, with Scharner lurking dangerously.
The hosts launched a swift counter-attack through N'Zogbia down the left and the ex-Newcastle ace ducked inside before finding Cleverley, whose low drive was easily held by Carson.
Di Matteo made a tactical change in the 67th minute as Giles Barnes came on at right wing, in place of the hobbling Scharner, with Brunt shifting to central midfield.
But Albion were undone by a sucker punch on 70.
Wigan broke from a Baggies free-kick and N'Zogbia managed to find Moses, who took a touch before sliding the ball past Carson and inside the far post.
In response, Di Matteo brought Simon Cox on for Morrison three minutes later.
Albion pressed for an equaliser during the latter stages and Thomas' left-wing cross found its way to Reid in the 81st minute and he was unlucky to see his goalbound shot deflect off Gohouri and loop just wide of the far post.
At the other end, Thomas' tackle on Cleverley fell into the path of substitute Franco Di Santo, who somehow fired wide of the right-hand post from 12 yards, with the whole goal at his mercy.
In the 90th minute, Brunt's free-kick was half-cleared by Wigan and Cox volleyed the loose ball wide of the right-hand post from 20 yards.
Albion's final shot at bagging a point came in the dying seconds of stoppage time when Brunt's right-wing corner crept through to Barnes, who fluffed his chance, before substitute Marc-Antoine Fortune's shot was saved by Al Habsi and Roberto Martinez's men cleared.
WIGAN (4-5-1): Al Habsi; Stam, G Caldwell (S Caldwell 17), Alcaraz, Gohouri; N'Zogbia, Gomez (Moses HT), H Thomas, Diame, Cleverley; Rodallega (Di Santo 77). Subs not used: Kirkland (gk), Watson, Boselli, Figueroa.
ALBION (4-2-3-1): Carson; S Reid, Ibanez, Tamas, Shorey; Mulumbu (Fortuné 89), Scharner (Barnes 67); Brunt, Morrison (Cox 73), J Thomas; Odemwingie. Subs not used: Myhill (gk), Cech, Dorrans, Zuiverloon.
GOALS: WIGAN - Moses (70).
BOOKINGS: WIGAN - S Caldwell (foul 44). ALBION - Scharner (foul 51).
REFEREE: A Taylor (Manchester).
ALBION STARMAN: Jerome Thomas.
PIC: MIDFIELD MUSCLE...Mulumbu tussles with Cleverley