Karlan Grant scored twice as West Brom came from behind to beat QPR 2-1 and go top of the Championship at The Hawthorns.
But West Brom were gifted a route back into the game after a mistake by goalkeeper Seny Dieng led to the equaliser.
Dieng allowed a shot to his near post from Grant to squirm from his grasp and into the net for Albion's equaliser in the 75th minute, cancelling out Andre Gray's opener after just 43 seconds.
Grant then scored the winner in the 88th minute.
Up until the equaliser, it looked like it was going to be a hard-luck story for West Brom, who dominated territorially and created numerous chances without having the decisive touch in front of goal.
At the Arena Stadium, hosts Coventry City went to second on the ladder with a 3-0 win over Peterborough.
Swedish striker Viktor Gyokeres netted a brace in three minutes soon after Gustavo Hamer's opener to blow away Darren Ferguson's men, who remain one place outside the bottom three.
The Sky Blues, who came into the clash off the back of a 1-1 draw against Millwall last weekend, made two changes as Jamie Allen and Martyn Waghorn returned to the starting line-up in place of Ben Sheaf and Matt Godden.
The top two gain automatic promotion to the Premier League at the end of the season with the next four teams involved in a playoff to determine the third team to advance to English soccer's glamour league.
Australian Associated Press