Albion tasted home defeat for just the third time this season as Wigan Athletic halted the Baggies’ six-game unbeaten run on a frustrating afternoon at The Hawthorns.
Latics skipper Sam Morsy scored the game’s only goal as the in-form visitors earned a valuable three points in their pursuit of Sky Bet Championship survival.
Slaven Bilić named an unchanged side from Tuesday’s convincing 2-0 victory over Preston North End with Rekeem Harper continuing to deputise for suspended Romaine Sawyers.
After a placid opening it was the visitors who were first to threaten on eight minutes when Sam Johnstone was twice forced into low saves to deny Sam Morsy and Joe Williams from close range.
The Baggies were almost ahead moments later. Harper chased down a stray bouncing ball in the middle of the park to prod through Matheus Pereira who fired straight at David Marshall from 15 yards.
Gavin Massey should have fired the visitors in front on 19 but his diving-header from Kieffer Moore’s deep right-wing cross cannoned against the upright.
Wigan continued to show the confidence of a side that have lost just one of their last seven fixtures with Massey again causing problems two minutes later - cutting in from the left before dragging wide of the near post from 20 yards.
The Baggies were limited to half-chances throughout the opening 45 minutes, but Filip Krovinović probably thought he’d scored when his close-range shot was blocked inside the six-yard box.
Pereira played in Robinson with a defence-splitting pass seven minutes before the interval but Marshall was quick off his line to narrow the angle for the on-loan winger.
The two teams continued to exchange blows following the restart, Jamal Lowe flashing wide with a 51st-minute strike.
Matt Phillips’ introduction from the bench on 55 minutes almost paid immediate dividends when he played in Robson-Kanu but Albion’s top scorer was pursued and halted by Leon Balogun with referee Tony Harrington waving away appeals for a penalty.
The Latics continued to give as good as they got and carved out another chance just shy of the hour mark when Gary Roberts forced a near-post save from Johnstone.
Krovinović sent a driven low shot whistling past the right upright from 25 yards on 66 which large sections of the sell-out Hawthorns crowd thought had gone in.
But then the visitors took a 73rd-minute lead with Latics skipper Morsy blasting home a volley after a melee inside the Albion area.
Hal Robson-Kanu did his best to find an Albion equaliser but could not find the power to beat Marshall from Dara O'Shea's right-wing cross which the Latics stopper routinely saved.
The Baggies continued their push for a late leveller but it was Wigan who almost scored once more, with Sam Johnstone forced into a superb stoppage-time save to deny Lowe.
ALBION: Johnstone; O’Shea, Ajayi, Hegazi (Bartley 43), Townsend; Livermore, Harper (Phillips 55); Pereira, Krovinović, Robinson (Grosicki 61); Robson-Kanu.
Subs: Bond; Furlong, Austin, Barry.