Leeds United's 16-year exile from the Premier League is over after West Brom's 2-1 loss to Huddersfield Town saw Marcelo Bielsa's side promoted from the Championship.
Anything but a West Brom win would have seen leaders Leeds promoted and they fell behind inside four minutes, Chris Willock volleying home after goalkeeper Sam Johnstone failed to deal with a free-kick.
The Baggies levelled in controversial fashion before the break, Jonas Lossl claiming an offside Grady Diangana was in his line of sight when he palmed the ball up for Dara O'Shea to head in.
But substitute Emile Smith Rowe scored an 86th-minute winner for the Terriers, who are now virtually safe as they look to avoid the ignominy of back-to-back relegations.
West Brom will drop out of the automatic promotions places if Brentford avoid defeat in their penultimate match at Stoke City on Saturday.