West Brom missed the chance to go back to the top of the Sky Bet Championship after scraping a point at struggling Wigan.
The Latics - with manager Paul Cook in the stands, serving a one-game touchline ban - were the better side for virtually all the game.
After Jamal Lowe had squandered a gilt-edged opportunity in the first half, Wigan deservedly led through a bizarre goal five minutes after the break.
Skipper Sam Morsy's shot was tipped on to the post by goalkeeper Sam Johnstone, who then unwittingly diverted the ball into his own net.
Michael Jacobs hit the bar for Wigan shortly after and the home side paid for their profligacy with a goal even more unusual than the opener.
Wigan goalkeeper Jamie Jones temporarily turned his back on the action to take a drink in his goal, and turned to see Antonee Robinson's backpass rolling towards him.
Jones picked the ball up and was immediately penalised, with Jake Livermore touching the free-kick to Charlie Austin, who slammed home from six yards.
After that, it was end-to-end stuff, but neither side were able to nick all three points, with Wigan remaining in the bottom three.
And they will wonder what might have been after starting the game by far the brighter, appealing for three penalties inside the opening quarter.
Twice Josh Windass was sent tumbling to the ground, by Kyle Bartley and Semi Ajayi respectively, only for referee Oliver Langford to wave play on.
Then, left-back Robinson raced into the box and saw his cross hit the hand of a defender, but again the official was unimpressed.
Wigan came closer still when Windass' shot from 25 yards was parried out by Johnstone into the path of Lowe.
But from eight yards out and the whole goal to aim at, the forward fired his effort straight at the West Brom keeper.
Lowe was involved again when, after a superb ball from Windass out to Robinson, Jacobs couldn't get his shot away. The ball fell to Lowe, who could only stab straight at Johnstone.
A fantastic cross from Lee Evans, on his wrong foot, was headed just over by Gavin Massey and West Brom would have gone into the break wondering how they were still level.
That changed within five minutes of the restart, with the home side taking a deserved lead.
There was an element of fortune about it, with Morsy's brilliant strike from 30 yards finding the net via the back of Johnstone.
And Wigan were so close to making it 2-0 before the Baggies could regroup, with Jacobs shooting against the bar, before Massey headed the rebound into the arms of Johnstone.
Then came the incident that changed the game, with the Baggies levelling with their first real attempt on goal.
And after that it could have gone either way, Massey having the best chance, only to direct a header straight at Johnstone.
What the managers said...
Wigan's Paul Cook: "It's a massive, massive step forwards for us. In the situation we're in - irrespective of the goal we conceded - I think the level of performance was there from us for everyone to see.
"And that's the most pleasing thing for me as a manager. At the same time, you have to be disappointed it's not all three points. We're on about a West Brom team that's outstanding…they've lost one in 20, they score a lot of goals and don't concede many. But tonight, Jamie Jones has caught one header, and I don't think they've had another effort (apart from the goal). That's great credit to our team play, our work ethic and our desire."
West Brom's Slaven Bilic: "We have to be honest enough to admit we weren't as good tonight as we've been so far. And by the way, we have to give great credit to Wigan for the way they played. We started slowly, and we have to admit we didn't deserve anything more than a point.
"I said to the guys at the end of course we are disappointed, we are all gutted. But we have to take this as a blessing, because we know we can't be like this again. We didn't get big-time punished, so we have to take the point as a good one."