Ben Mee scored the decisive goal as Burnley brought Tottenham crashing back down to earth.
Mee beat Cristian Romero in the air at the back post to head in a free kick from Josh Brownhill and earn the Clarets their third win of the season.
Harry Kane had struck the bar with a header for Tottenham shortly after the break but Spurs, who beat league leaders Manchester City on Saturday, were unable to find a way past Burnley keeper Nick Pope.
Burnley remain within the relegation zone but move up to 18th place on 20 points, two points behind Newcastle United and Everton but with a game in hand on the former.
The result underlines just how far Tottenham have to go under Antonio Conte only days after the high of beating Manchester City away.
