Defender Dean Huijsen scored the only goal as Bournemouth beat Tottenham to climb above them in the Premier League table.
The 19-year-old was left unmarked at the back post to head home Marcus Tavernier's inswinging corner on 17 minutes.
Huijsen's goal extended Spurs' poor record of dealing with set-pieces, and prompted manager Ange Postecoglou to shake his head ruefully on the touchline.
Postecoglou's side had started well, with Dominic Solanke prominent as he returned to the Vitality Stadium following his £65m summer move.
Solanke, who was greeted by a smattering of boos, had two of the first three shots for Spurs, but they lost their way after Huijsen's goal, and Tavernier and Evanilson had chances to extend Bournemouth's lead in the first half.
Spurs regrouped after the break and pushed for an equaliser by bringing on captain Son Heung-min for Pape Matar Sarr, which led to chances for James Maddison, Pedro Porro and Dejan Kulusevski.
But the north Londoners gave away more chances than they created in the closing stages, and Evanilson had a goal ruled out for offside.
Victory took Bournemouth up to ninth - a place above their opponents.
Spurs' problems were compounded when Ben Davies left the field with what appeared to be a hamstring problem, leaving Postecoglou with just one fit centre-back before Sunday's derby against Chelsea.
Bournemouth, too, have an injury issue to deal with, with manage Andoni Iraola saying after the game that defender Marcos Senesi would be out for a long time with a "massive injury in the quad".