Metz end Lyon's run as PSG take Ligue 1 lead
Rudi Garcia's side had come into Sunday's late match on the back of 16 league games without defeat, knowing that a win would have put them back in the lead of France's top flight.
However Aaron Leya Iseka struck in the final minute to snatch the points for resilient Metz, who had to withstand a second-half onslaught before finally prevailing and moving ninth.
"We pushed, they pushed, and we were rewarded for our efforts. We knew that we would have little of the ball and that we would have to counter well, and that's what we did," said Belgian Leya Iseka.
The loss leaves Lyon third, two points behind PSG and Lille, whose own late goal from Jonathan David secured a 2-1 win over Reims.
Lyon should have taken the lead six minutes before the break when Karl Toko Ekambi was fed by Tintotenda Kadewere on a breakaway attack.
Cameroonian Ekambi, who had forced a good save from Alexandre Oukidja three minutes earlier, successfully cut inside to fashion himself a shooting opportunity but could only blast over.
Three minutes later Metz twice came close to taking a shock lead, first hitting the post following a Farid Boulaya cross before Marcelo charged back to block Lamine Gueye's shot on the line.
With 16 minutes remaining Ekambi slammed home what he thought was the opener when the ball fell to him after fine play between Memphis Depay and Thiago Mendes.
However after a long VAR review the goal was ruled out for Houssem Aouar straying offside when Mendes shot and then pressuring Metz defender Fabien Centonze, who had nodded the ball out to Ekambi.
Islam Slimani had the perfect chance to win the match with seven minutes left of his Lyon debut but he shanked his shot, and Oukidja then did brilliant to keep out Aouar's close range effort after fine work from Memphis Depay.
That allowed Leya Iseka to claim a shock win for Metz.
- David strike for Lille -
Earlier David pounced in the first minute of stoppage for Lille to tap home after Xeka's powerful low drive was spilled by Reims goalkeeper Predrag Rajkovic to put Lille on 42 points, equal with champions PSG.
Jonathan Bamba's long-range leveller two minutes after the break gave Lille a chance to snatch the win after Arber Zeneli had given Reims a 35th-minute lead with a cross that bamboozled home stopper Mike Maignan.
Monaco are six points off the lead in fourth after Wissam Ben Yedder's brace gave them a 3-2 win over Montpellier on Friday.
The Principality club are level on 36 points with fifth-placed Rennes, who earlier on Sunday fought back from going a goal down after just three minutes at Brest to win 2-1.
Saint-Etienne are just four points above the relegation zone after a 1-0 defeat at Strasbourg.
The 10-time French champions are 16th and winless in five league matches thanks in part to a missed 10th-minute penalty from Ryad Boudebouz.
Ludovic Ajorque scored the winner for the team from Alsace just before the half-hour mark.
Nantes are hovering above the drop zone after drawing 1-1 at home with Lens, with Gael Kakuta's 81st-minute leveller for the away side denying Raymond Domenech a first win in charge of the hosts.
The former France coach has guided Nantes to three straight draws since his much-derided appointment last month, with his team battling a run of games without a win that stretches back to early November.
Bordeaux strolled to a thumping 3-0 win at Nice, who are also without a win in five.