A five-minute hat-trick deep in the final quarter from Reading striker George Puscas saw Wigan Athletic crash to their third home defeat in a row.
Latics had led through Joe Garner's first goal of the season, a close-range effort 11 minutes before half-time.
But the game completely changed when the visitors were awarded a controversial penalty with 12 minutes to go.
Chey Dunkley was adjudged to have handled the ball in the box, and Puscas sent the spot-kick down the middle of the goal.
Puscas then evaded Charlie Mulgrew to put his side ahead two minutes later.
Then, with seven minutes to go, he completed his hat-trick with a cool finish from close range, after good work from Garath McCleary.
The late turnaround sparked unsavoury scenes in the home ends, with the fans chanting 'you're getting sacked in the morning' at boss Paul Cook, whose side remain in the bottom three.
Full reaction and analysis to follow.