Shane Long deservedly fired Steve Clarke’s side in front with his 11th goal of the term in the 29th minute but Arouna Kone clawed the visitors level six minutes before the break.
The Baggies looked back on track when Gareth McAuley, who was named Player of the Season six days ago, headed his side back in front in the 50th minute.
But there was to be a real twist in the game.
Sub James McArthur made it 2-2 with his first touch in the 58th minute and James McManaman fired what proved the game’s decisive goal ten minutes from time.
Albion will regard this as an opportunity missed after letting a game they looked comfortable in slip from their grasp.
Eighth entertained 18th on a glorious Black Country afternoon, with the two teams chasing very different goals.
Wigan were looking to close the five-point gap to safety while Clarke’s side were aiming to break the 50-point barrier in the Barclays Premier League for the first time in the club’s history.
Clarke made three changes from the 3-0 romp at Southampton, with Markus Rosenberg, back-from-suspension Youssouf Mulumbu and Billy Jones coming in for the banned Marc-Antoine Fortune, benched James Morrison (groin) and injured Steven Reid, who missed out altogether.
Wigan made two alterations as Ronnie Stam and ex-Baggies loan star Ben Watson, who was given a warm welcome by the home fans, replaced the injured Maynor Figueroa and benched McArthur.
An even warmer reception was afforded former fan-favourite Paul Scharner, who made his first return to The Hawthorns after being released last summer.
There was a party atmosphere inside a packed stadium before kick-off which was undoubtedly fuelled by local rivals Wolves' relegation to League One after their 2-0 defeat at another ‘Albion’, Brighton.
Buoyed on by a sea of noise, the Baggies attacked with real intent during the opening stages and Joel Robles had to pull off a smart save at his near post to deny Rosenberg – making only this third league start for the club – a tap-in from Long’s centre.
Robles had another save to make in the tenth minute when Graham Dorrans’ 25-yard free-kick flew through the Wigan wall but straight at the Latics’ No.1
Albion were well and truly ‘at it’ and a minute later Romelu Lukaku seized on Stam’s misplaced header but volleyed wide from the edge of the box.
Rosenberg had enjoyed a lively opening and he threatened again when he had a low 15-yard drive blocked by Emmerson Boyce from Long’s pull-back.
Then, on 15, Rosenberg did well to squeeze over a cross from the left and Long was denied a certain goal by Jean Beausejour’s last-ditch clearance.
Ben Foster did not have a shot to save until the 16th minute – and it was as straight-forward as they come – when he held onto McManaman’s weak shot from 20 yards.
The Albion keeper had to make a far more awkward stop two minutes later, though, when he dived full stretch to his left to push away Kone’s 25-yard rocket.
The Baggies were soon back on the attack but several promising moves were undone by the final ball.
Wigan stemmed the tide in the 27th minute when Kone swung in a dangerous cross which Shaun Maloney headed well wide.
But Clarke’s men deserved to be ahead and they broke the deadlock with a stunning counter-attack on 29.
Claudio Yacob halted Scharner’s run with a terrific tackle and Lukaku sent Rosenberg scampering away with a sublime through-pass. The Swede spotted Long’s far-post run and whipped over a pinpoint centre which the former Reading ace tapped home from close range.
Wigan responded immediately with a neat right-wing move but Players' Player-of-the-Season McAuley kept his team ahead by beating Kone to Stam’s near-post centre and conceding a corner.
The visitors produced their best moment yet on 38 when Maloney curled an inviting 20-yard free-kick just wide.
And they were level 60 seconds later. Referee Lee Probert waved play on after Jones upended James McCarthy and Beausejour whipped in an inch-perfect centre which Kone headed past Foster.
That proved the final notable action of the first half and the second 45 got off to a rather inauspicious start – until the Baggies regained the lead on 50.
Dorrans swung over a free-kick from the right and McAuley got in front of Kone to plant a downward header past Robles from eight yards.
However, Albion’s lead lasted just eight minutes. Maloney whipped in a gorgeous cross from the left and McArthur planted home a diving header from close range with his first touch since coming on as a sub a minute earlier.
The Baggies were almost back in front on the hour-mark when McAuley rose highest to head a Dorrans corner inches over.
But Wigan created a chance of their own on 64 when Kone was well off target with a header from Maloney’s set-piece.
Clarke made a double change a minute later, with Jerome Thomas and Morrison replacing Lukaku and Rosenberg.
Albion had struggled to get any momentum going since the interval but they almost went in front for a third time on 73. Mulumbu did well to keep possession and find Jones in space and the right-back surged towards the box before seeing his low drive kept out by Robles’ legs.
However, it was Wigan who added to the scoring next to take the lead for the first time. In the 80th minute, Maloney skipped down the left and his low cross was tucked home from six yards by McMananman.
Back came Albion and Mulumbu wasn’t far away with an 18-yard curler that whistled just wide of the far post.
And Robles had to pull off the save of the game in the final minute to keep out Dorrans’ 25-yard volley.
Robles was at it again moments later when, from Dorrans’ corner, he tipped over Liam Ridgewell’s towering header.
In stoppage time, Albion had loud penalty appeals turned away when Jones appeared to be barged over by Wigan sub Roger Espinoza as he tried to connect with Thomas’ left-wing centre.
There was even more drama in the sixth minute of stoppage time. With Foster up for a Dorrans corner, McAuley again won the aerial duel in a crowded penalty area to head goalwards – only to see his effort cleared off the line by McArthur.
Moments later, Probert below the final whistle – leaving Albion scratching their heads as to how they had ended up pointless.
ALBION (4-3-3): Foster; Jones, McAuley, Olsson, Ridgewell; Yacob, Dorrans, Mulumbu (Brown 86); Long, Rosenberg (Morrison 65), Lukaku (Thomas 65). Subs not used: Myhill (gk), Tamas, Dawson, Odemwingie.
WIGAN (3-4-3): Robles; Boyce, Watson, Scharner; Stam (Golobart 57), Gomez (McArthur 57), McCarthy, Beausejour (Espinoza 74); McManaman, Kone, Maloney. Subs not used: Al Habsi (gk), Caldwell, Di Santo, Henriquez.
GOALS: ALBION – Long (29), McAuley (50). WIGAN – Kone (39), McArthur (58), McManaman (80).
BOOKINGS: ALBION – Jones (foul 39), McAuley (foul 75), Brown (foul 90+4). WIGAN – Maloney (foul 57), Golobart (foul 67), Scharner (foul 90+5).
REFEREE: L Probert (Wiltshire).
ALBION STARMAN: Markus Rosenberg.