A disastrous opening 20 minutes from Guingamp ensured Marseille kicked off their Ligue 1 season with a 3-1 victory.
Andre-Pierre Gignac opened the scoring for Elie Baup's men, before Dmitri Payet, signed from Lille in the summer, scored a double to put the visitors firmly in control.
Guingamp, who were playing their first game in the top flight for nine years, had looked to have given themselves a lifeline when they were awarded a penalty, but Mustapha Yatabare was unable to convert.
The striker did atone for his earlier miss though, when he found the net with 16 minutes left but it was too little, too late.
Saint-Etienne began life without Pierre-Emerick Aubameyang, who scored a hat-trick on his Bundesliga debut with Borussia Dortmund, with a 1-0 win at Ajaccio.
Brandao did his best though to help the ASSE fans forget about the Gabonese international, scoring the only goal of the game to give Christophe Galtier's men an opening day victory.