ALBION's seven-match unbeaten run in the Sky Bet Championship came to an end as they were beaten 1-0 at Wigan Athletic.
Josh Windass drilled home the only goal of a heated encounter in the 74th minute as the Baggies tasted league defeat for the first time since the end of August.
Defeat at the DW Stadium was also only the second occasion this term Darren Moore's side, the highest goalscorers across all top four divisions in England, have been blunted - the last coming in their most recent defeat two months prior.
Jake Livermore was shown a red card in the 85th minute for a second bookable offence, at the end of a clash which saw a further seven yellow cards.
The Baggies, who were backed by a fantastic travelling support of 3,750 in Greater Manchester, host Derby County on Wednesday looking to make amends.
Albion showed one change from their 4-1 victory over Reading before the international break, captain Chris Brunt recalled in place of Gareth Barry, who had picked up a slight niggle.
And it was the visitors who started brightly, Jay Rodriguez seeing his header saved by Christian Walton before Harvey Barnes, fresh from making his England Under-21 debut, was denied by a last-ditch sliding block.
Gary Roberts flashed a ball across the face of goal for the Latics, who went on to dominate the first half, Windass clipping a chance wide having been sent clear by Nick Powell.
Wigan looked to scramble home a break and Powell headed over before the latter was brought down on the edge of the penalty area, with home players and supporters alike calling for a penalty.
Sam Johnstone then got down well to keep out Windass as a first half, which saw five yellow cards dished out, ended goalless.
Head Coach Moore was forced into a change just four minutes into the second period, Tosin Adarabioyo replacing Craig Dawson, who picked up a knock before the break.
As was the case at the start of the first half, the Baggies dominated play initially following the restart before the hosts then forced a couple of smart saves from Johnstone.
And it was the Baggies goalkeeper who was forced to get down low and produce a fine stop to keep out Windass in the 72nd minute.
Yet he could do nothing just minutes later as Windass was sent through in space, he beat Ahmed Hegazi and drilled low into the bottom corner.
Hal Robson-Kanu and Kyle Edwards were introduced off the bench as Albion looked for a route back into the encounter.
But it was not to be and Livermore was given his marching orders in the closing stages.
ALBION: Johnstone, Dawson (Adarabioyo 49), Hegazi, Bartley, Mears (Edwards 78), Livermore, Brunt (c), Gibbs, Barnes, Rodriguez, Gayle (Robson-Kanu 76).
Subs: Myhill, Townsend, Field, Hoolahan.