Antonio Conte says Tottenham will have to "improve a lot" and it "won't be easy to fight for something this season" after they were held by a Southampton side who played for more than 50 minutes with 10 men.
Spurs fell behind at St Mary's when James Ward-Prowse cut across a bouncing ball to volley a swerving shot past Hugo Lloris for a superb opener.
But the game turned when Mohammed Salisu fouled Son Heung-min in the box to earn a second booking in 12 first-half minutes and allow Harry Kane to level from the penalty spot.