Lyon increased the pressure on Paris Saint-Germain and Marseille ahead of Le Classique with a comfortable 3-1 win over 10-man Guingamp on Saturday.
The majority of the focus in France this weekend is on Sunday's meeting between the two arch-rivals and title challengers at the Stade Velodrome.
However, Lyon produced a timely reminder of their own championship credentials by leapfrogging PSG to the top of the table with a routine triumph at the Stade du Roudourou.
Nabil Fekir opened the scoring in the 26th minute in fortuitous circumstances, as his 25-yard effort was spilled into the net by Guingamp goalkeeper Jonas Lossl before Lyon top scorer Alexandre Lacazette then doubled the lead with a 39th-minute penalty,
The France forward powered a shot into the roof of the net from 12 yards after being awarded what looked to be a soft spot-kick having appeared to clip his own heel following a tussle with Baissama Sankoh.
Guingamp were reduced to 10 men a minute before the interval, Christophe Kerbrat seeing red for a rash challenge on Jordan Ferri.
Clinton N'Jie steered Lyon's third into the bottom-right corner after 61 minutes, with Claudio Beauvue's 80th-minute reply for Guingamp proving nothing more than a consolation.
Lyon are now two points ahead of PSG and four clear of Marseille, but at the other end of the table Toulouse's survival hopes were hit by a 3-2 loss at Metz.
Modibo Maiga's hat-trick, which came after Wissam Ben Yedder had put Toulouse ahead, proved enough for Metz to move off the bottom with a first league win since November 1, with Marcel Tisserand sent off for the visitors before Tongo Doumbia pulled one back late on.
That defeat saw Toulouse miss the chance to move out of the bottom three and leapfrog Lorient, who were beaten 3-0 by Brittany rivals Rennes.
Fellow strugglers Evian salvaged a 2-2 draw at Nice thanks to Kevin Gomis' 78th-minute own goal, although they would have taken all three points had Daniel Wass converted a 10th-minute penalty.
Reims remain just three points above the drop zone following a 3-1 reverse at Lille, who triumphed despite Divock Origi's missed spot-kick.
Elsewhere, Montpellier overcame Bastia 3-1 thanks in part to penalties from Lucas Barrios and Anthony Mounier.