Marco Silva has claimed that Olympiacos were rewarded for a tireless performance in their 3-2 victory over Arsenal at the Emirates Stadium.
Arsenal twice scored equalisers after falling behind but Alfred Finnbogason clinched all three points as Olympiacos sent the Gunners to the bottom of Group F.
After securing the win in dramatic style, manager Silva was quick to praise the attitude of his players.
"I'm very happy with the result because it was a very tough encounter," he told reporters. "Olympiacos had never won on English soil and our players had to dig deep in order to believe in their chances and get what they wanted out of the game.
"We deserved this victory because we worked a lot in order to achieve it.
"It was important for us to get the opening goal and then respond quickly after both Arsenal goals. The key factor today was our endurance. We ran a lot, we knew how to battle and how to remain determined to hold onto the result we deserved until the end."
Olympiacos had failed to record a win on their 12 previous trips to England.