Free-scoring Monaco moved level on points with Ligue 1 leaders Nice after thrashing local rivals Marseille 4-0.
The hosts made a blistering start to the derby and found themselves three goals up at the interval.
Gabriel Boschilia kickstarted things in stunning fashion when he curled an unstoppable free-kick over the wall and beyond Yohann Pele in the 23rd minute.
Then, following some great work down the right by Bernardo Silva, Valere Germain popped up in the box to head the Portugal international's pinpoint delivery beyond Pele just before the half-hour mark.
And Germain capped off a confident first-half Monaco display when Radamel Falcao diverted Djibril Sidibe's delivery his way to bend in his second goal of the match just inside the far right post.
Marseille looked to respond in the opening stages of the second half, but Florian Thauvin's deflected effort ended up the wrong side of the post before Bafetimbi Gomis saw his volley gathered by Danijel Subasic.
Even when l'OM looked sure to score, after Clinton Njie's superb pass picked out Remy Cabella, the visitors found an in-form Subasic who did superbly to turn away the former Newcastle forward's effort.
Monaco wrapped up the points in added time when Pele did well to claw at Germain's lob but Guido Carrillo was on hand to head home as the home side moved onto 32 points alongside Nice, who face Bastia on Sunday.