Two managers coming under increasing scrutiny collided at the London Stadium, with Nuno Espírito Santo facing the unthinkable prospect of being sacked twice in the same season ahead of this showdown against his former club.
And when Alphonse Areola made a stunning save early on to deny Neco Williams in the opening exchanges, the Claret and Blue faithful sensed another long evening was in store.
However, the Hammers struck first in fortuitous fashion, as Murillo turned the ball into his own net after Tomáš Souček flicked on Crysencio Summerville’s corner at the near post.
Taty Castellanos then had a chance to make his two and mark his West Ham debut with a goal, but failed to connect with Souček’s cross.
It was an encouraging first half for the hosts, though Forest almost equalised just before half time, when Callum Hudson-Odoi’s superb right-footed effort cannoned off the bar.
There was an action-packed start to the second half, as West Ham were denied a second before conceding an equaliser in the space of four frantic minutes.
Summerville’s sublime drilled volley past Matz Sels was ruled out for a marginal offside call against Castellanos in the build-up, and Forest took full advantage of that reprieve when Nicolás Domínguez’s looping header from Elliot Anderson’s corner restored parity.
Nuno called upon another one of his January reinforcements to steer the game back in their favour after introducing Pablo for his debut from the bench, but the Brazilian frontman failed to find the target with his close-range strike.
From there, both sides pressed in search of a potentially decisive goal, with further chances for Domínguez and Kyle Walker-Peters, before Murillo made an excellent defensive block to thwart Jarrod Bowen.
A draw seemed inevitable, but there was to be one final twist, as Areola was penalised for a clumsy collision with Morgan Gibbs-White.
The World Cup hopeful stepped up to seal Forest’s comeback victory, putting a significant seven-point cushion between themselves and the vanquished Hammers, who have now won only two of their last 14 PL games (D3, L9) – a sequence that looks to have almost sealed the makeup of the bottom three, despite the 2025/26 campaign being only just past the halfway mark.
Flashscore Man of the Match: Nicolás Domínguez (Nottingham Forest)