Brighton held their nerve to secure a huge 2-1 victory over Southampton in a major boost to their Premier League survival hopes.
The visitors went ahead twice and dominated in the second half particularly. This result means they leapfrog fellow strugglers Newcastle United ahead of a crunch clash next weekend.
Both sides created early chances, but it was Brighton who struck first through Lewis Dunk's powerful header. Fraser Forster had denied Neal Maupay moments earlier, but he couldn't stop the visiting captain's effort from the resulting corner.
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The goal seemed to wake Southampton up, with Takumi Minamino soon beginning to have a bigger impact on the game. Brighton's lead lasted just 11 minutes; it was csncelled out by Che Adams' third goal in as many games. He volleyed home after James Ward-Prowse's corner wasn't cleared.
Brighton defended well as the hosts pushed on for a second; Kyle Walker-Peters and Ryan Bertand were stretching the play well. But the Seagulls ended the half stronger, and saw a great chance go begging.
Dan Burn drove up the pitch from left-back and slipped in Pascal Gross, but the German slipped at the key moment and Forster diverted his shot wide.
Graham Potter made a tactical change and his side did retake the lead four minutes short of the hour, having dominated since half time. Trossard finished emphatically after great work by Adam Lallana and Danny Welbeck, forcing the Saints to regroup again.
Southampton soon looked as though they had run out of ideas, having won just once in their previous 11 league games, and but for a late Ward-Prowse effort and a quick VAR check for a potential penalty after Walker-Peters went down, they caused Brighton very few problems.
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The Brighton boss recognised where his side were going wrong in the first half, having surrendered momentum despite going ahead. Southampton were stretching the play through their wing-backs and allowing creative players like Minamino to impact the game centrally. Replacing Burn with Andi Zeqiri turned the game and gave Brighton a crucial win.
MAN OF THE MATCH - Adam Lallana (Brighton)
Back on his old stomping ground, Lallana was superb. Potter played him in a deeper midfield role, and while eventual match-winner Trossard was absent for much of the first half, he was pulling the strings at key monents. He had a hand in the second goal and his guile will be key for the Seagulls in the run-in.
Southampton: Forster 6, Walker-Peters 6, Bednarek 5, Vestergaard 6, Bertrand 7, Armstrong 6, Diallo 5, Ward-Prowse 6, Minamino 6, Tella 6, Adams 7 Substitutes: Redmond 5, Djenepo 5, N'Lundulu n/a
Brighton: Sanchez 7, Veltman 7, White 6, Dunk 7, Burn 6, Lallana 8, Bissouma 7, Gross 6, Trossard 7, Welbeck 7, Maupay 6 Substitutes: Zeqiri 7, Propper 6, Moder n/a
16' - GOAL! Lewis Dunk heads home from a corner. Big goal for Brighton.
27' - GOAL! Che Adams levels it up with a neat volley after Brighton fail to clear Ward-Prowse's corner.
41' - CHANCE! Brighton should be 2-1 up. Dan Burn drives inside and finds Gross, but his shot lacks conviction. He is slipping as he takes it and Forster deflects away for a corner.
56' - GOAL! Trossard fires home. Lovely pass by Lallana and touch by Welbeck. 2-1 to the strugglers.
- Brighton have scored more than once in a Premier League game for the first time since Januaey 2, 11 games ago.
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