In what had been billed as something of a grudge match ahead of the game after a fiery away leg last month, David Moyes and his side sealed a crucial three points and confirmed they will be playing European football in some capacity after Christmas.
Here's how David Moyes's side rated at the London Stadium...
Lukasz Fabianski 6
One hairy moment coming for a cross late on. Did not have a save to make.
Vladimir Coufal 6
One or two crucial bits of defensive work at the far post. Delivery from wide was off.
Konstantinos Mavropanos 6
A drama-free display was just what was needed after a tough afternoon at Brentford.
Nayef Aguerd 7
Might have had a hat-trick of headers by half-time after meeting a string of Ward-Prowse corners. His most solid defensive display for some time, though. Read the game well.
One terrific dart past three men earned a free-kick in prime territory .
Edson Alvarez 7
Tried to lift the tempo of some cautious play. Picked up his customary booking - it's now 7 in 14 West Ham matches since his summer arrival.
James Ward-Prowse 7
Set-pieces were excellent as ever but scuffed a good first-time chance from Bowen pull-back. One vital bit of covering when Olympiacos broke three-on-two and then made Paqueta's winner.
Mohammed Kudus 7
West Ham's liveliest player in the first-half, so good and keeping the ball alive when appearing to have overrun. Booked for blatant dissent.
Lucas Paqueta 8
Not at his best but still most likely to play the killer pass - then got on the end of one from Ward-Prowse to settle the contest.
Said Benrahma 6
Forged a couple of openings but some dreadful decision-making.
Jarrod Bowen 6
Again deployed as a centre-forward. Made West Ham's best chance from open play with cut-back for Ward-Prowse.
Tomas Soucek (Alvarez 80') N/A
Brought on to see out the game with Alvarez on a booking.
Maxwel Cornet (Benrahma 84') N/A
Divin Mubama (Kudus 89') N/A
Unused: Areola, Anang, Johnson, Cresswell, Kehrer, Ogbonna, Fornals, Ings