West Ham's Champions League hopes were dealt a major blow despite a fine late equaliser from Said Benrahma against Brighton.
The game burst into life in the final 10 minutes, with Danny Welbeck scoring a breakaway goal for Brighton in the 84th minute, which was cancelled out three minutes later by Benrahma's curling shot.
The point from the 1-1 draw means the Hammers are five points behind fourth-placed Chelsea with only two matches to play.
Leeds swept to a 4-0 win over Burnley to strengthen their grip on a top-half place.
After Mateusz Klich gave Marcelo Bielsa's side the lead on the stroke of half-time, Leeds punished the Clarets after the break as Jack Harrison added a second before claiming the two assists when Rodrigo came off the bench to score a brace.
The result gave Leeds a four-point cushion over 11th-placed Aston Villa before Dean Smith's side head to Crystal Palace on Sunday.
Nathan Tella scored his first goal for Southampton in their 3-1 win over already-relegated Fulham.
The 21-year-old came off the bench to net Saints' second, while Fulham's consolation came from 18-year-old Fabio Carvalho, his maiden goal for the Cottagers.
Che Adams scored a first-half opener for Saints, while substitute Theo Walcott restored their two-goal advantage with a clinical finish eight minutes from time.