Elsewhere in France, Florian Thauvin starred for Bastia once more, as Nice kept up their hopes of the Champions League with a stunning 4-3 win over Toulouse in a frantic game
Marseille toasted the re-opening of their Tribune Ganay at the Stade Velodrome with a 1-0 victory over Bordeaux which saw them provisionally cut the gap at the top to just four points.
It was OM's 10th 1-0 victory in the league this season, a testament to Elie Baup's determined side who remain in the hunt for the Ligue 1 title despite a squad lacking sorely in depth or quality.
The game's only goal came via Andre-Pierre Gignac, who struck his second winner in a week, latching onto Benoit Cheyrou's exquisite through ball before beating Cedric Carrasso.
Andre Ayew and Foued Kadir spurned further chances for the hosts, though goal-shy Bordeaux were also again profligate in front of goal, with Nicolas Maurice-Belay heading wide.
OM rise to second, and face Lille next weekend, as they seek a late charge in their quest for a tenth Ligue 1 title.
NANCY 1-0 TROYES
Nancy picked up a brilliant third win in a row, as their late surge to avoid the drop gathered further pace with a 1-0 win over Troyes at Stade Marcel Picot.
The relegation six-pointer had been settled by the single goal, with Romain Grange curling a sumptuous free-kick past Yohann Thuram-Ulien on 67 minutes.
Thuram-Ulien also denied Nancy a second, producing a fine stop from Benjamin Mouandjo's angled half-volley as Nancy rolled on in the fight against relegation.
Troyes remain bottom, as Nancy rise to 18th, a point from safety with four wins in their last five. They enjoyed just one victory from 19 before Christmas.
TOULOUSE 3-4 NICE
Nice kept the heat up on Lyon and Saint-Etienne with a fine 4-3 win in a highly dramatic and blistering encounter at Stadium Municipal as both sides ended with ten men.
The seven-goal thriller began in the first minute when Eric Bautheac fired the visitors in front, before Wissam Ben Yedder equalised seven minutes later, and Etienne Capoue gave the hosts the lead in a frantic opening.
Bautheac struck his second, this time from a free kick before half-time to equalise once more. Dario Cvitanich then put Nice 3-2 ahead, seeing his shot deflect off Pavle Ninkov and over Ali Ahamada.
Ahamada was then shown a red card for bringing down Mahamane Traore, and the drama continued right up until the death as Ben Yedder made it 3-3 on the stroke of full-time.
Alexy Bosetti was also shown a red card for a crunching challenge on Cheikh M'Bengue, but Kevin Anin ensured Claude Puel's men escaped the madness by side-footing past substitute goalkeeper Olivier Blondel in the fourth minute of injury time to steal victory, and with it, a renewed hope to reach the Champions League.
SOCHAUX 0-0 AJACCIO
Sochaux moved up to 16th, but failed to put daylight between themselves and the bottom three following a turgid 0-0 draw against Ajaccio.
The Corsicans were defensively superior throughout, with Guillermo Ochoa pulling off a fine save from Giovanni Sio's goal-bound header.
Adrian Mutu spurned the visitors' best chance, with Simon Pouplin denying the away side as the match ultimately ended in a 0-0 draw - a result which isn't beneficial to neither side with seven games left.
MONTPELLIER 3-1 VALENCIENNES
Champions Montpellier are now three points off the Europa League spots following a comfortable 3-1 win over struggling Valenciennes.
Souleymane Camara broke the deadlock just 19 minutes into the game, beating Nicolas Penneteau with a fine finish, before Opa Nguette got the better of Geoffrey Jourdren with a fine turn and shot into the back of the net.
Jonas Martin ensured the second half started positively, hitting the post after good work from Younes Belhanda before Daniel Congre headed in from the Moroccan's ball to put MHSC 2-1 up.
Belhanda himself capped off a fine game with the third as Rene Girard's men step up their efforts for the final seven games of the season.
BASTIA 4-0 STADE BRESTOIS
Bastia are on the brink of securing their Ligue 1 status for next season following a fine 4-0 victory over Brest, who drop into the bottom three after a one-sided encounter at Stade Armand Cesari.
Wahbi Khazri drilled home a free-kick four minutes before the break, firing past the wall and Joan Hartock to give the Corsican side the lead.
Jerome Rothen's threaded ball to starlet Florian Thauvin saw the soon-to-be Lille midfielder easily beat Hartock, before doubling his tally after latching onto Anthony Modeste's flick-on and firing the ball past the goalkeeper.
Thauvin was in brilliant form, scoring twice for the third game running, before Modeste himself got onto the scoresheet from the spot, with Hartock sent off for the foul.
SAINT-ETIENNE 1-0 EVIAN
Saint-Etienne rose above their rivals Lyon and into the final Champions League spot with a 1-0 win over Evian.
It proved to be Sainte's first win in four games, though they are unbeaten in 16, as the hosts scored despite much resistance from a stubborn Evian outfit.
Bertrand Laquait, the Evian goalkeeper was in imperious form, denying Pierre-Emerick Aubameyang and Yohan Mollo on various occasions, but managed to be beaten by Romain Hamouma's good finish.
The visitors were not without their chances however. Yannick Sagbo headed over narrowly their best chance of the game late on, as Sainte moved into the top three following a narrow win.
STADE DE REIMS 1-0 OLYMPIQUE LYONNAIS
Stade de Reims picked up a vital 1-0 win over Olympique Lyonnais on Sunday, effectively ending Remi Garde's side's title hopes.
The visitors, without a win in five, are on their worst run of Ligue 1 form since September 1993, having not won in five, and falling out of the top three.
Grzegorz Krychowiak struck the winner from the spot early into the second half after Diego was fouled by Milan Bisevac in the area.
Clement Grenier brought produced a fantastic save from Kossi Agassa, though Diego also hit the post for Hubert Fournier's side as Lyon ultimately fell to yet another defeat, with their Champions League hopes now hanging by a thread.
LILLE 5-0 LORIENT
Lille thrashed Lorient 5-0 at Grand Stade Lille Metropole on Sunday evening to make it a four-way fight to secure the final Champions League spot.
Buoyed by Lyon's earlier defeat in the day, LOSC knew that a win against Christian Gourcuff's side - whose own European ambitions have waned recently - would take them closer to the top three.
And they set about their business positively from the off, as Salomon Kalou and Dimitri Payet netted quickfire goals within the first eight minutes.
Lorient never got going, and fell further behind after the half-hour, Lucas Digne tucking away a penalty for his first Ligue 1 goal, before Kalou made it 4-0 on 33 minutes. Payet was in brilliant form again, with his curling shot hitting the post before the Ivorian international cleaned up for his second.
That effort was also mirrored in the fifth goal as Ronny Rodelin tapped home from Kalou's initial shot which hit the woodworl.
Lille's charge for a Champions League place has seen them win seven of their last eight games.