Leandro Trossard’s superb late goal gave Brighton a gutsy win that dealt a blow to Tottenham’s hopes of finishing in the top four.
Following a game of few clear-cut chances, Trossard swerved into the Spurs area in the final minute of normal time before producing a fine finish past Hugo Lloris.
Steven Bergwijn then missed a chance to equalise at the start of stoppage time – one of the home side’s rare opportunities.
Spurs stay in fourth, just ahead of Manchester United and Arsenal, while Brighton – in 10th – are on course for their highest-ever top-flight finish.
Graham Potter’s side enjoyed the better of a first-half where Spurs looked oddly sluggish despite not having played for nearly a week, but after the hosts appeared to improve in the second half, they were undone by a combination of poor defending and fine skill from Trossard.
The Belgian eluded Eric Dier before opening up his body to send a shot with the outside of his right foot low into the far corner of the net.
Spurs did not look anything like the side that came into the game on a run of four consecutive wins -which had started with a 2-0 victory at Brighton, and in which they had scored 14 goals and conceded just two.
Harry Kane and Son Heung-min were shackled effectively Brighton, with the South Korean not managing a shot on target until nearly an hour in – with an effort that was comfortably blocked in the Albion area.
They were slow out of the blocks and while more fired up after the break, presumably after manager Antonio Conte had aired his views to the team at half-time, they lacked the kind of sharpness required to unlock the Brighton defence.
It was an opportunity missed for Spurs, as rivals Arsenal lost at Southampton later on Saturday, while Manchester United moved above the Gunners and just three points behind in fifth with a win against Norwich.
Spurs face Liverpool on 7 May and then their north London rivals five days later in games that could decide whether they play in the Champions League next season.
Brighton’s two wins in north London in a week will have banished memories of a worrying slide down the table caused by six straight defeats through February and March.
Trossard had put Albion on the way to a memorable win at Emirates Stadium seven days earlier, and the 27-year-old’s sixth goal of the season ensured his side will also have the best-ever haul of away points in the Premier League.
They have earned 25 of their 40 points so far on the road, and they pulled together impressively to execute Potter’s plan to frustrate and ultimately deny Spurs.
Their 29 goals scored so far is the lowest of any team in the top half of the table, but they seem on target for the club’s best-ever finish in the top flight – and with games to come against Manchester United and West Ham, they could still have a say on how the European places pan out.
Source – BBC Sport