Lyon reeled off their seventh consecutive Ligue 1 win on Sunday, a 2-0 defeat of 10-man Metz pushing them four points clear, as Paris Saint-Germain moved level with second-placed Marseille.
Paris Saint-Germain midfielder Zlatan Ibrahimovic (R) vies with St Etienne defender Theophile Catherine (L) during the French L1 football match on January 25, 2015 at the Geoffroy Guichard stadium in Saint-Etienne
Zlatan Ibrahimovic scored the only goal in a 1-0 win at St Etienne that allowed champions PSG to move level on points with out-of-sorts Marseille who lost 2-1 at Nice on Friday.
PSG and Marseille have 44 points after 22 games, four behind Lyon, who the Parisians will play at the Gerland Stadium in two weeks' time.
A 31st minute penalty from Alexandre Lacazette and a late second from Corentin Tolisso proved the undoing of Metz who drop to bottom of the table.
The only downside for Lyon came when Lacazette, the league's top scorer with 21 goals, had to come off with a thigh problem minutes after his spot-kick, awarded for defender Guido Milan's foul on Rachid Ghezzal.
Milan picked up a harsh red card for his indiscretion.
Coach Hubert Fournier confirmed that Lacazette would miss next week's trip to Monaco and was doubtful for the game against PSG the following week.
"We'll have to wait for a full report from the club's medical staff before we know how long he will be out," said Fournier.
But Fournier expressed satisfaction with the result.
"We feel like we've done a job today. We were under a lot of pressure because everyone thought we were going to win, but Metz posed us a lot of problems," he said.
- Nine goals for Ibrahimovic -
Ibrahimovic once again proved the undoing of St Etienne, after he also scored the goal that eliminated them from the League Cup on January 13.
This time the win came thanks to a penalty awarded after Jeremy Clement handled in the area, with Ibrahimovic stepping up to convert after 60 minutes for his ninth league goal this season.
It condemned St Etienne to their first defeat going back to October 5, as they sit fourth eight points behind Lyon.
Despite the closeness of the result, the Parisians dominated, and with defender Thiago Silva in form confirmed they have regained some of their solidity in defense.
The visitors could have doubled their account after 70 minutes but Italian midfielder Marco Verratti's shot was blocked by St Etienne defender Paul Baysse, and six minutes later a Cavani effort hit the bar.
Elsewhere Sunday, Evian helped their hopes of avoiding relegation with a 1-0 win over Toulouse which pushed them three points clear of the drop zone.
Caen midfielder Julien Feret helped the Normandy side claim their second straight 4-1 victory, this time against his former club Rennes with three decisive passes and a goal five minutes from time.
Feret set up Sloan Privat to head in after just four minutes, and was hand to tee up Lenny Nangis five minutes after the break before netting a third himself, as Damien Da Silva compounding Rennes' misery with a minute to go.
Caen move off the bottom of the table to 18th place as midtable Rennes notched up a sixth game without a win to set themselves up a nervous trip to PSG next weekend.