Monaco recorded their biggest away win in Ligue 1 with a 7-0 hammering of Mets at the Stade Saint-Symphorien to move top of the table.
Leonardo Jardim's men made a fine start when Thomas Lemar opened the scoring after just seven minutes and Valere Germain doubled Monaco's lead midway through the first half after an assist from Joao Moutinho.
Bernardo Silva made it three in the 39th minute and Metz were dealt another blow at the hour mark when Cheick Doukoure was given his marching orders.
There was no let-up in the final half an hour as Fabinho converted a penalty in the 68th minute, before Guido Carrillo netted a double to pile even more misery on the home side.
Brazilian youngster Boschilia had the final say in the 89th minute to complete Monaco's record league away victory.
"Metz continued to try to score after conceding that third goal and we took advantage of the space we go and scored seven goals," Jardim commented on his side's win.
"We are having a good start to the season. We have to keep working hard to improve."
Second-placed Nice can leapfrog Monaco again if they beat Lorient on Sunday.