Brennan Johnson scored deep into additional time to deliver a come-from-behind Premier League victory for Tottenham against Brighton.
Tottenham responded well to falling behind, creating a raft of chances, but Jason Steele made several good saves to deny the in-form Richarlison and Dejan Kulusevski, while James Maddison curled narrowly wide.
The momentum remained firmly in Spurs' favour when the second half got under way with Rodrigo Bentancur, Maddison and Timo Werner attempting efforts at goal as the majority of the action took place deep in Brighton territory.
They continued to probe and that pressure eventually told when Sarr latched on to a lovely through ball from Kulusevski before finishing at the second attempt after his initial shot was deflected on to the post.
Captain Son Heung-min was introduced after the equaliser, making his first appearance of 2024 for Spurs after returning from duty with South Korea at the Asian Cup, and the forward had a major hand in the winning goal as he laid the ball across goal for Johnson to convert.
Tottenham manager Ange Postecoglou, speaking to BBC Match of the Day, said: "It's fair to say that we are still a work in progress but we had a world-class player in Son [Heung-min], who makes the most difficult ball look simple to set up Brennan [Johnson].
"It was a great finish for us and the supporters."
Joyous stoppage-time scenes for Spurs
No team has conceded more than Tottenham's tally of eight goals in the 90th minute or later in the Premier League this season, but Spurs were on the other side of that equation on Saturday as they showed grit and determination right to the finish.
Postecoglou spoke this week about having a strong and healthy squad available for the first time in a while with the likes of Son, Sarr and Yves Bissouma returning from international commitments at the Asian Cup and Africa Cup of Nations, while Van de Ven made his fifth successive appearance after a 10-game absence due to injury.
The Australian manager also outlined how key it was to prevent Brighton from settling into a rhythm early on but his side failed to heed that warning as the visitors created early chances and moved the ball neatly through the thirds of the pitch.
After conceding their sixth penalty of the season - the most of any team in the league - which was converted by Gross, Tottenham sprang into life and everything seemed to click with Maddison creating from midfield, Sarr making driving runs into the final third and Richarlison causing problems in and around the box.
Spurs were well clear on the shot count at half-time but lacked a clinical edge, something they managed to correct after the break as initially Sarr and then Johnson got the job done to keep the pressure on Villa in the race for a Champions League berth.
Away problems persist for Seagulls
Brighton were without manager Roberto de Zerbi for the game as the Italian was suspended after being shown his third yellow card of the season and opted not to travel after dental surgery this week, so assistant Andrea Maldera was deputising.
It all seemed to be going so well when Gross calmly converted from the spot but clear-cut openings were few and far between for the remainder of the match.
The Seagulls, to their credit, were always willing to press and showed plenty of energy but the absence of top-scorer Joao Pedro, who missed out with a hamstring injury, left them wanting in the final third.
Coming up short on the road is becoming a common narrative for the south coast club, winning just one of their last 10 away from home in the league, and De Zerbi will be eager to address that issue as he looks to steer Brighton back into Europe next term.
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