Marseille came from behind to win 3-2 at Monaco with a last-gasp goal from Valere Germain on Sunday, ending a dismal run against their main Ligue 1 rivals under coach Rudi Garcia.
Kostas Mitroglou headed home from a pinpoint Dimitri Payet cross to give Marseille the lead on the stroke of half-time.
But Monaco replied with two quickfire goals after the break as Youri Tielemans equalised and Colombia forward Radamel Falcao knocked in a loose ball from close range after the Marseille defence got into a tangle.
Substitute Florian Thauvin coolly turned a low cross to equalise before Germain headed in from a corner to win the game against his former club in the 89th minute.
Germain spent six seasons at Monaco before joining Marseille last year.
Marseille had not won any of their previous 11 matches against the trio of Paris Saint-Germain, Lyon or Monaco with three draws and eight defeats since Garcia took over in October 2016.
PSG are top in Ligue 1 with a maximum 12 points from four games after beating Nimes 4-2 on Saturday. Marseille are fifth with seven points, while Monaco have four.