ALBION threw away a first-half lead to gift basement boys Wigan three precious points.
The Baggies deserved their 33rd-minute opener, which came courtesy of Steven Reid's stunning free-kick - the right-back's first goal of the season.
But the Latics were level just four minutes later when Victor Moses curled home a fine equaliser from inside the box.
And Reid's afternoon went from ecstasy to agony 12 minutes after the break when he was guilty of conceding Albion's fourth penalty in as many homes games for a foul on Moses, which Jordi Gomes converted.
The Baggies piled on the pressure after going behind and went frustratingly close to levelling when Shane Long headed against the inside of the post - but they couldn't muster an equaliser.
The two teams were separated by six points before kick-off as 14th entertained 20th.
Peter Odemwingie was handed his first start in five games as Roy Hodgson made one change from the QPR draw, with Graham Dorrans dropping to the bench.
Wigan also made one alteration. Antolin Alcaraz returned from a three-match ban to replaces Steve Gohouri.
Albion started like a house on fire and Chris Brunt went close inside 67 seconds when he stuck out a left leg and diverted Odemwingie's left-wing cross just over.
The Baggies skipper went even closer in the third minute. After Wigan had only partially cleared a James Morrison free-kick, Brunt seized on the loose ball 20 yards out and saw his ferocious drive brilliantly tipped onto the bar by Ali Al Habsi.
Brunt's ensuing corner came straight back to the Northern Ireland international and his second cross was headed just wide by Jonas Olsson.
Wigan earned some respite with a period of possession play but the Baggies were back on the attack on 12 and clever link-up play between Shane Long and Odemwingie created a half chance for the latter, who shot wide from a tight angle.
However, the goalmouth action suddenly dried up as the game settled into a mundane passage of play.
The Latics were enjoying plenty of possession without threatening Ben Foster's goal while Albion were being frustrated in their attempts to unlock the visiting defence.
It wasn't until the 24th minute that Wigan recorded an effort at goal, with Moses well off target with an ambitious 30-yarder.
A minute later, a series of ricochets in the Albion box almost set up a chance for Connor Sammon, but Foster was alert to the danger and gathered the ball at the striker's feet.
Albion sprang back into life on 27 and the lively Jerome Thomas was unfortunate to see his goalbound effort deflected over by Gary Caldwell's outstretched leg after being teed up by Odemwingie.
From Morrison's ensuing corner, Caldwell again came to Wigan's rescue when he diverted wide Gareth McAuley's downward header.
Albion had easily been the most threatening team and deservedly took the lead on 33 minutes with a peach of goal.
The referee's assistant displayed 20/20 vision to spot a Caldwell foul on Long just outside the Wigan box. Brunt looked the likely candidate to take the free-kick but he left it to Reid, who curled a sublime effort over the Latics wall and inside the left-hand post. The accuracy of the strike meant Al Habsi could only stand and watch the ball enter his goal.
The home hordes, who took advantage of the club's reduced prices to pack out the stadium, were on their feet again moments later when Nicky Shorey found Odemwingie inside the penalty area. The Nigerian swivelled and shot but Caldwell was in the way again and deflected the ball wide.
Wigan regrouped and Moses tried his luck from distance for a second time, producing a similar result.
But Roberto Martinez's men DID claw themselves level on 37.
Youssouf Mulumbu looked to have made a vital interception when he slid in to cut out Mohamed Diame's low cross, but the ball flew straight to Moses who beat Foster all ends up with a sublime 15-yard curler.
The equaliser perked Wigan up and Foster had to take evasive action by rushing out of his area to clear after Moses had burst through the middle of the Albion defence.
Albion started the second half purposefully and Long created a chance out of nothing when he charged down Caldwell's clearance. The Ireland striker dinked the ball to the back stick, only for Maynor Figueroa to get there a split second before Brunt and head clear.
But the game once again entered a scrappy period, with neither side able to stamp their authority on proceedings.
And Albion were in big trouble on 57 when they conceded a penalty for the fourth home game running after Reid tripped Moses inside the box.
Gomes made no mistake from 12 yards, coolly sending Foster the wrong way.
It was a hammer blow but Albion responded by winning a succession of corners. However, they came to naught.
Wigan launched an attack of their own in the 63rd minute but Gomes shot tamely at Foster from 20 yards.
Moses had Foster back-pedalling moments later with an audacious chip but the on-loan Blues man was equal to it.
Only a terrific save by Al Habsi kept Wigan ahead on 68.
Thomas played in Shorey and from the left-back's cross, Long saw an eight-yard header brilliantly pushed wide by the Wigan keeper.
Albion were now pouring forward at will and their goal agony increased in the 79th minute when Long saw a fine header from Thomas' left-wing cross hit the inside of the beaten Al Habsi's post and bounce to safety.
The chances kept coming and Olsson failed to hit the target with a presentable heading opportunity from Shorey's centre.
Former Wigan man Paul Scharner, who had appeared as an 84th-minute sub, missed an even better chance three minutes from time when he directed a free header from Thomas' cross over from inside the six-yard box.
ALBION (4-4-2): Foster; Reid, McAuley, Olsson, Shorey; Brunt (c), Mulumbu (Dorrans 66), Morrison (Scharner 84), Thomas; Odemwingie (Tchoyi 81), Long. Subs not used: Fulop (gk), Jones, Dawson, Cox.
WIGAN (4-4-2): Al Habsi; Stam (McArthur 70), Alcaraz (Gohouri 67), G Caldwell (c), Figueroa; Diame, McCarthy, Gomez, Jones; Sammon (Di Santo 80), Moses. Subs not used: Pollitt (gk), Watson, Maloney, Rodallega.
GOALS: ALBION - Reid (33). WIGAN - Moses (37), Gomes (penalty 57).
BOOKINGS: ALBION - Reid (foul 53), Dorrans (simulation 88). WIGAN - Gomez (unsporting behaviour 21).
REFEREE: M Dean (Wirral).
ALBION STARMAN: James Morrison.