Tottenham slipped to a first away defeat since July after a mistake by Ben Davies helped Royal Antwerp leapfrog their Europa League opponents to go top of Group J.
Davies, making his 200th Spurs appearance, was easily dispossessed by Dieumerci Mbokani, whose pass allowed Lior Refaelov to smash past Hugo Lloris.
Flat and uninspired, Spurs struggled to carve out chances and Jose Mourinho made four changes at the start of the second half in an attempt to inject some urgency into the side.
But it could have been worse for Tottenham, Mbokani somehow blazing over from three yards out before Harry Kane was sent on in an attempt to rescue the game.
Simen Juklerod also missed a fine chance after being sent clean through as Spurs failed to score for the first time since the opening weekend of the season.
Mourinho’s side are three points behind Royal Antwerp in Group J after two games, level on points with LASK, who beat Ludogorets 4-3.
Having embarked on a 10-match unbeaten run since losing at home to Everton on the opening weekend of the season, this was as bad as Spurs have performed in a long time.
Mourinho showed his displeasure by making a string of changes at the break.
Dele Alli was handed his first start since 24 September but is still to finish a match this season after being hauled off at half-time in two of the three matches he has started.
Alli at least created a chance for Carlos Vinicius before he was replaced, former Manchester United full-back Ritchie de Laet producing a fine challenge before the Spurs player could shoot.
Netherlands winger Steven Bergwijn and Argentine midfielder Giovani lo Celso did manage attempts before the interval but both were comfortably dealt with by keeper Jean Butez
Kane replaced Bale, who has also yet to complete 90 minutes since re-joining on a season-long loan from Real Madrid.
The Wales forward has yet to reach peak fitness after missing a number of games but there was little creativity from the four-time Champions League winner in Belgium.