Olympiakos kept their one-point lead over Panathinaikos at the top of the Greek Super League on Sunday courtesy of a 3-0 home win over bottom club Panthrakikos.
Arsenal will put one of the best Champions League records on the line when they face Olympiakos Piraeus in a showdown for second spot in Group F on Wednesday.
A weekend of surprise results across Europe's big leagues saw Bayern Munich's unbeaten run come to an end, Napoli knocked off top spot in Serie A and Manchester City toppled in the Premier League where Leicester City are the new leaders.