Francisco Soares opened the score in the sixth minute against Fenerbahçe in Istanbul, while Giorgos Masouras added another two goals for Olympiacos in the 62nd and 68th minutes.
Masouras, the match’s MVP, almost came away with a hat trick as the Turkish club’s keeper deflected a one-on-one shot with his foot.
Olympiacos picked up its second straight win, as it beat Antwerp 2-1 at home in the inaugural match of Group D.
In another Group D clash, Frankfurt claimed a 1-0 away win against Antwerp at Bosuilstadion as the goal came from Goncalo Paciencia’s stoppage-time penalty.
Olympiacos top the group with six points, Frankfurt are in the second spot with four points, Fenerbahçe are in third place with one point and Antwerp are at bottom of the group with no point.