West Ham, which was safe from any relegation worries thanks to Ipswich Town's loss to Newcastle United, thought it had secured a first win in just fewer than two months, but Brighton had other plans.

Yasin Ayari had given the Seagulls a 13th-minute lead, but West Ham responded well, with Tomas Soucek smacking the crossbar with a towering header shortly after.

Simon Adingra saw a second Brighton goal disallowed in the 36th minute.

Alphonse Areola had made a double save to deny Pervis Estupinan and Mats Wieffer before the winger rifled in, but a video assistant referee (VAR) check confirmed Danny Welbeck had interfered with the initial effort from an offside position.

West Ham's revival began in the second half, with Mohammed Kudus slotting Jarrod Bowen's low cross through Bart Verbruggen's legs just three minutes after the restart.

Tomas Soucek completed their comeback in the 83rd minute, rising high in the crowd at the far post to thump Bowen's curling delivery into the net.

However, Kaoru Mitoma equalised in the 89th minute, nodding in from close range after being left unmarked on the edge of the six-yard box.

Baleba then sent the home fans into raptures with his stunning stoppage-time strike from distance, leaving former Brighton boss Graham Potter scratching his head on the sidelines.

Brighton moved up to ninth, keeping its slim European hopes alive, while West Ham stays 17th, but 15 points clear of the bottom three with only four games left to play.

Potter voiced his frustration at the result and the way the season has gone for West Ham side.

“The ability to sustain [our performance] is the biggest factor. We did a lot of good things,” he said.

“We have been done by two goals from outside the box. We created chances, scored two goals, but you need to sustain that and that is the challenge for us.

“Nobody wants to hear about the positives but there were some over the course of the game, but I am in too much pain to talk about the positives.

“But the emotion of the result is hard to take. We just have to accept that feeling and deal with it.

“We have lost, thrown points away at the end and we are hurting.”

When asked about Premier League safety being confirmed, Potter added: “We have to acknowledge the season we are having is a bad one. The fact we have stayed clear is good but not good enough. We have to do better.

“We are in the middle of a bad season, and psychologically, the players are affected.

“Physically, there is a challenge to sustain the good things in a game, and there were good things. But when you lose in that manner it is hard to see that.”

Brighton boss Fabian Hurzeler, meanwhile, was delighted with the resilience his team displayed.

“This is a great feeling and I'm very happy for the supporters, team and staff because they worked really hard,” he said.

“They have suffered in the last period but today they got what they deserved. We always had the belief and trust in our ability to win the game. At the end they didn't force it, they stuck to their game plan and made good decisions. So, the credit goes to my players.”