Marseille put a trying week behind them in the best possible fashion on Sunday night, with a 3-0 victory at home to Paris Saint-Germain that put a sizeable dent in their arch rivals' title hopes.
OM's Champions League ambitions were compromised by a loss to Olympiakos in mid-week, before Andre-Pierre Gignac was dropped over a row with coach Didier Deschamps, but they stopped the rot to condemn PSG to a third league loss.
Loic Remy broke the deadlock early on and with PSG's expensively assembled team floundering in defence and toothless in attack, Marseille took full advantage through second-half goals from Morgan Amalfitano and Andre Ayew.
"I'm thinking about our supporters, who had lots of anger but who I think will have really enjoyed tonight," said Deschamps.
"After the disappointment of Wednesday, producing this performance against a team second in the league is a huge satisfaction."
Defeat for PSG kept them in second place and allowed Montpellier to hold on to top spot in Ligue 1, while Marseille climbed one place to ninth, seven points below the top three.
The away side had started brightly at Stade Velodrome but Marseille took the lead from their first sight of goal in the ninth minute.
Cesar Azpilicueta was given time to cross from the right wing and his centre was met by an imperious downward header from Remy, who claimed his seventh goal of the season.
PSG's only chance of note in the first half saw Mohamed Sissoko drill a 25-yard half-volley against the post with Steve Mandanda beaten.
OM lost Remy to an ankle injury but they were given few problems by PSG, whose record signing Javier Pastore struggled to impose himself, delighting the home fans with some uncharacteristically clumsy touches.
The Argentine was taken off before the hour, along with a furious Kevin Gameiro, but their replacements Mathieu Bodmer and Mevlut Erding had been on the field for a matter of minutes before the hosts doubled their lead.
Amalfitano picked Blaise Matuidi's pocket in midfield and then gathered a pass from Remy's replacement Jordan Ayew before finding the bottom-left corner with an unerring drive.
PSG's misery was complete in the 83rd minute, with Amalfitano crossing for Andre Ayew to find the net with a header that flicked off defender Marcos Ceara before trickling past Salvatore Sirigu.
"They have something that we don't -- that grit, that rage, that ability to do damage in 50-50s," rued PSG coach Antoine Kombouare.
"We've lost six points (including 1-0 loss at home to Nancy last weekend), but we've only played 15 games, we're second, and the important thing will be our capacity to react."
Earlier, Lisandro Lopez scored his first goals since his return from an ankle injury sustained in August as Lyon salved their own Champions League heartache with a 3-0 win at Auxerre that saw them reclaim fifth place.
Tuesday's 0-0 draw with Ajax practically extinguished OL's Champions League hopes, but they recorded their first win since the end of October via a brace from Lisandro and a late Michel Bastos strike.
"I was hoping for this reaction after the delicate period in the league and the Champions League," said Lyon coach Remi Garde.
"We saw a Lisandro who was very clinical and who was able to guide the team towards victory."
In the day's other afternoon kick-off, Lorient climbed above Saint-Etienne into seventh place by beating second-bottom Nice 1-0 thanks to a 63rd-minute penalty by Arnold Mvuemba.
Montpellier pulled three points clear of PSG at the summit on Saturday as newly capped France striker Olivier Giroud claimed a hat-trick in a 3-1 win at Sochaux.
Reigning champions Lille held on to third place by beating Brest 2-0 through goals in either half from Dimitri Payet and Moussa Sow.