Tottenham captain Son Heung-min called Spurs lastest defeat "unacceptable" and said his fellow players "need to take responsibility" after they dropped points from a winning position for a fifth consecutive game.
Ange Postecoglou's men deservedly took an early lead at home to West Ham on Thursday night but were ultimately beaten 2-1 following a second-half comeback.
No team has dropped more points from winning positions in the Premier League this season than Tottenham, who have relinquished 16.
And Spurs' run of five matches without a win has caused the Lilywhites to drop from first, with a five-point lead at the top of the table, to fifth.