Simon Stone, BBC Sport
There have been some very memorable nights at the London Stadium during West Ham's three-year European odyssey.
No-one will argue this latest triumph was one of them.
It was a hard watch for long periods with, a couple of Said Benrahma efforts and a second-half chance for James Ward-Prowse apart, little in the way of threat to the Olympiakos goal.
But they did produce the one genuine moment of quality in the game.
Ward-Prowse's chipped pass was exquisite. Lucas Paqueta timed his run perfectly, even though it needed VAR to confirm it, and the Brazilian's over the shoulder finish was brilliantly executed.
It deserved to win the game. Paqueta still has those betting charges hanging over him but he remains someone who can lift a game above the ordinary.