Ben Johnson and then Tomas Soucek both scored in reply to goals from Neal Maupay and Lewis Dunk as the Hammers had to recover from a sluggish start.
David Moyes named a rather conservative side as he looks to keep his players fresh over Christmas, but was saved following the introduction of substitutes Manuel Lanzini and Andriy Yarmolenko at the break.
Here is how Jack Rosser rated the West Ham players…
Hard to blame Fabianski for the two Brighton goals, made a few routine saves in the first half too.
Hardly put a foot wrong, another solid display from a player following in the footsteps of Ogbonna to become one of the more reliable men in the West Ham side.
Soft defending against Maupay for Brighton’s opener, should have done more to prevent the French forward from being allowed to turn.
Worked desperately hard to get the Hammers further up the pitch but is missing Arthur Masuaku ahead of him.
Tireless runner down the right hand side and often on hand with a last-ditch challenge at the back. Crossing was rather wayward going forward.
His goal masked over an unusually sluggish performance, but the Czech is always a danger in the box and delivered once more.
Not a game suited to the West Ham captain. Played as a No10 but too slow on the break. A surprise he lasted until half time before being replaced.
Not his best day. Tried to get forward and played a couple of nice crosses but West Ham often struggle to get going when he’s not on it.
Couldn’t get forward too much in the first half but enjoyed far more space after the break and took his first Premier League goal well. Should be more confident when trying to beat a player.
West Ham didn’t have enough of the ball to allow Bowen much of a chance to create, but when there were openings the winger was nowhere near effective enough.
Continues to try hard but very little was going the striker’s way this afternoon. Very isolated in the first half.
Picked up the pace dramatically after his introduction, clever play for Johnson’s goal too. Deserves a go from the off soon.
Dangerous cross in the build up to Johnson’s goal and gave the Brighton defenders something to think about after a very comfortable first half.
Subs not used: Benrahma, Snodgrass, Dawson, Fornals, Diop, Fredericks, Randolph