Ligue 1's last unbeaten run was ended Sunday when Lille followed up their midweek triumph over Milan with a 3-2 defeat at Brest, who was cheered on by fans in overlooking buildings.
Lille remains second in the French top-flight five points behind Paris Saint-Germain and one above Rennes but may be overtaken when Nice host Monaco in a south coast derby later Sunday.
The team that thumped AC Milan 3-0 at the San Siro on Thursday possibly hadn't left enough as in the tank to see off Brittany outfit Brest, who had lost three in a row.
Ronael Pierre-Gabriel got his first professional goal with a header for the opener on 15 minutes and Brest raced to a 3-0 lead before half-time with goals from Romain Perraud and Irvin Cardona.
Christophe Galtier's side never gave up however and earned a penalty in first-half injury time with Turkish striker Yilmaz Burak slotting home.
He grabbed another goal on 57 minutes to set up the eventually doomed chase as the home side were cheered on by noisy neighbours in an adjacent building.
On Saturday, Angel Di Maria scored twice as Paris Saint-Germain made short work of Rennes despite a raft of absences in a 3-0 win with the Argentine striking in each half and Moise Kean scoring the other.
PSG's win was their eighth in a row in Ligue 1 and came as under-fire coach Thomas Tuchel battles with an injury crisis that has left him without the likes of Neymar, Kylian Mbappe and Marco Verratti.