Spurs are now seven points behind Leicester City with three Premier League fixtures remaining, meaning a single win for the Foxes will secure their first ever top flight crown.
Mauricio Pochettino's team appeared to be pushing their title rivals all the way after convincing wins against Manchester United and Stoke City in their previous two outings and Craig Dawson's first half own goal suggested it would be business as usual in north London.
The home side had plenty of chances to double their advantage but, as is so often the case with players who put through their own net, Dawson redeemed himself by powering home the Baggies' equaliser 17 minutes from time.
The result leaves Spurs needing a flawless final three matches and hoping that Leicester achieve the complete opposite to stand any chance of lifting the title and they may have to do so without the help of key midfielder Dele Alli, who was involved in an off the ball incident with Claudio Yacob.
Here's how the evening unfolded in pictures...