Memphis Depay got a goal and four assists as OL won 5-0 in Metz to go third - ahead of OM on goal difference - while leaders PSG were lucky to avoid defeat, Mathieu Debuchy's last-gasp own-goal breaking green-clad hearts.
Since beating direct rivals Marseille 3-2 in Week 30's Olympico, Olympique Lyonnais have stormed right back into the race for third and their Memphis Depay-powered 5-0 tour de force away to bottom club FC Metz on Sunday saw them pip OM to third place - albeit on goal difference alone - with six matches left to play.
"When you open the scoring in the first minute it makes life a lot easier, especially against opponents who are bottom of the table," explained OL boss Bruno Genesio, who opted for a brand-new 4-4-2 formation - with Depay and Bertrand Traoré in attack and top scorer Mariano Diaz on the bench - for the big win. "[On Depay, who turned in the first four-assist performance in Europe's top leagues in five years] He seems happy on the pitch and full of confidence. When you have talent like he has, and that much confidence, you get performances like his last two. But I also think that his position [as a central striker rather than the wide role his usually plays in 4-3-3 or 4-2-3-1] with more freedom and fewer defensive tasks, really helps him in that regard."
Der Zakarian sends warning
OL's win on Sunday afternoon put the pressure on Marseille to get a result at home to Montpellier on Sunday evening, but Rudi Garcia's side - who will be looking to overturn a 1-0 deficit in the second leg of their Europa League quarter-final at home to RB Leipzig on Thursday - couldn't break their visitors down and had to make do with the 0-0 that allowed OL to overtake them.
Embroiled in the race for fifth place and the UEFA Europa League berth that goes with it, Montpellier are up for the battle despite having drawn six times in an unbeaten league run of eight matches.
"Maybe our playing style isn't to everyone's taste but the main thing in football is to collect points and be effective," explained Montpellier boss Michel Der Zakarian, whose side have drawn 16 times this season. "We're fighting it out with five teams and there are six matches left - almost all against direct rivals. And they should be wary of us - we're tough to move around and we can hurt them."
Meanwhile Paris Saint-Germain had a chance to put the title race to bed [as they entertained Saint-Etienne at the Parc des Princes [a win for the capital club combined with defeat for Monaco on Saturday evening would have stitched up top spot], but Unai Emery's champions elect were on the back foot against Jean-Louis Gasset's Verts, conceding the opener and losing stopper Presnel Kimpembe to a red card late in the first half before a Mathieu Debuchy own-goal in the dying seconds saved their skins.
"It was a game of two very different halves. The first was our worst of the season," said PSG boss Unai Emery, no doubt pleased to see Rémy Cabella miss a penalty on the half-hour mark. "But the second half was different. We had chances and got the goal in the last minute. I am happy with the reaction from my team. The equaliser is maybe a little unfair but we deserve the point for the work we put in in the second half."
Monaco hold firm, Nice reined in by Rennes
However, even had Paris won, title celebrations would have to have been put on hold as Monaco got the job done against the Nantes side of former principality club coach Claudio Ranieri. The Canaris' Adrien Thomasson opened the scoring with a sublime volley but Radamel Falcao and Rony Lopes hit back to clinch the win and whittle PSG's lead down to 14 points.
OGC Nice were looking to keep their hat in the ring in the battle for fifth, and looked the goods as in-form hitman Alassane Pléa opened the scoring with his seventh goal in four matches, but direct rivals Rennes hit back through Benjamin Bourigeaud to maintain their grip on fifth.
Amiens on the brink of safety
Promoted Amiens took a step towards maintaining their top-flight status with a glittering display in their 3-0 beating of SM Caen, the side with the division's smallest budget climbing to 13th place on 37 points, eight clear of the relegation play-off place currently occupied by fellow promotees ESTAC Troyes, who remain in serious danger (18th on 29 points) after copping a 4-0 hiding at the hands of EA Guingamp.
Guingamp have been through a rough spell of late - they tasted nothing but defeat in March - but an excellent display saw them make it back-to-back wins and hang onto tenth place, locked on points with Dijon, who had South Korean superstar Changhoon Kwon's eighth of the season to thank for a 1-0 win away to relegation-threatened Toulouse (17th, one po9int above the play-off spot).
Angers and Strasbourg played out a relegation-accented 1-1 draw while Gustavo Poyet's Bordeaux broke a six-match winless run by beating 19th-placed LOSC 2-1.