Ligue 1's last unbeaten run was ended on Sunday when Lille followed up their midweek triumph over AC Milan with a 3-2 defeat at Brest, while Lyon downed local rivals Saint Etienne 2-1.
Lille remain second in the French top-flight five points behind Paris Saint-Germain and one above Rennes after suffering their first loss since February.
The team that thumped Milan 3-0 at the San Siro on Thursday failed to leave enough 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.
"We thought kick-off was going to be at 2p.m., we were wrong by an hour," said Galtier.
"When there's such a difference between the first and second half, there's only one person responsible and that's me. The starting XI was my choice and it didn't work at all."
Lyon moved into fifth place by beating strugging rivals Saint-Etienne 2-1 with Tino Kadewere fulfilling a his pre-match prediction that he'd score twice.
The 24-year-old Zimbabwean international scored in the 65th and 74th minutes after Lyon had fallen behind in the first half.
Saint-Etienne benefitted when Lyon goalkeeper Anthony Lopes managed to put through his own goal five minutes before the interval.
Lopes had saved well from a header by Denis Bouanga but then seconds later fumbled a cross from the same player across his own line.
Bouanga then missed a penalty in the 87th minute which would have given Saint-Etienne a point.
For Rudi Garcia's Lyon, it was a third win in four games while their local rivals slumped to a sixth successive loss.
"I'm happy for Tino who is appreciated by everyone. He has the qualities of a finisher," said Garcia.
Kadewere added: "I believe very strongly in God. I knew this was going to happen. It went very well tonight for me and for the team."
Monaco are sixth following a 2-1 victory at Nice.
Axel Disasi headed in a corner to put Monaco ahead on 23 minutes and Sofiane Diop punished a mistake by Stanley Nsoki to double the lead early in the second half.
Pierre Lees-Melou scored a consolation for Nice as Patrick Vieira's side were beaten for the first time in six matches.
Florian Sotoca scored two late goals as Lens salvaged a 4-4 draw at home to Reims, while Angers thrashed Nimes 5-1.
Nantes won 2-0 at Lorient but Dijon remain the only club without a victory despite a 1-1 draw at Metz.
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.