Leandro Trossard scored a stoppage-time winner as Brighton stunned top-four challengers, Tottenham, at the Tottenham Hotspur Stadium on Saturday afternoon.
Antonio Conte's side were hoping to extend their lead on the fourth position to five above Arsenal who lurk behind with two games in hand.
However, despite thumping Aston Villa 4-0 in their last outing, Conte's men fell to a resilient Brighton side who defeated Arsenal 2-1 in their last game.
Both sides were inseparable for almost 90 minutes as Graham Potter's men dominated the match with more possession and shots on target with Siprs failing to register a single shot on goal.
Son's attempt to hurt the visitors ended up being blocked until the 90th minute when their defence was caught napping and Trossard took advantage by curling a low shot past Lloris.
Tottenham have lost three of their last six home Premier League games (W3), as many defeats as they suffered in their previous 14 on home soil (W10 D1).
Brighton have won consecutive away league games for the first time since September 2021 and are now unbeaten in three Premier League games overall, winning the last two, after losing each of the six before that.
Spurs are now three points ahead of the Gunners, and seven ahead of West Ham who are levelled on points with seventh-placed Manchester United who have a game in hand.