Teenager Adrien Rabiot came off the bench to spur French Ligue 1 title-holders Paris Saint-Germain past promoted Guingamp 2-0 on Saturday, as the midfielder netted a decisive injury-time goal at the Parc des Princes.
PSG's stuttering start to the season appeared set to continue as the woodwork twice denied Laurent Blanc's side, but 18-year-old Rabiot struck a minute into stoppage time before Zlatan Ibrahimovic made the points safe.
The win takes PSG to within a point of leaders Marseille, who host third-place Monaco on Sunday.
Last year's top scorer Ibrahimovic, without a goal in his opening three matches, almost opened his account for the season inside two minutes as he struck the base of Mamadou Samassa's post from a free-kick.
Edinson Cavani then saw a glancing header at the near post turned over by Samassa before the frame of the goal again came to Guingamp's rescue as Thiago Silva headed the ensuing corner against the crossbar.
The visitors rarely troubled PSG bar for a deflected Moustapha Diallo effort that drew a routine save out of Salvatore Sirigu, but Guingamp goalkeeper Samassa grew increasingly busier as PSG pressed to break the deadlock.
The Malian international turned away another Cavani header after the interval before holding a low strike from Ezequiel Lavezzi, with Ibrahimovic then shooting wide after combining well with Cavani. However, Mustapha Yatabare almost stunned the home fans as Guingamp countered against the run of play with PSG indebted to Sirigu, the Italian expertly saving with the striker through on goal.
The visitors seemed set to come away with a commendable point, but they cracked a minute into stoppage time as Samassa could only claw Alex's header into the path of Rabiot, who stabbed home from close range for his first PSG goal.
Ibrahimovic added gloss to the score as he outmuscled Jeremy Sorbon to reach a hopeful ball forward before eluding Samassa and steering into an empty net.
Lyon's disappointing week was made even worse as Remi Garde's side followed up their midweek UEFA Champions League exit by crashing to a 2-1 defeat away to Evian.
Kevin Berigaud struck two first-half goals at the Parc des Sports in Annecy as Lyon slumped to a fourth straight defeat in all competitions.
The Evian striker notched the opener on eight minutes after latching onto Cedric Barbosa's through ball and added to his haul just after the half-hour as he exchanged passes with Danish winger Daniel Wass before slipping the ball under goalkeeper Anthony Lopes.
The visitors did manage to pull a goal back through Jordan Ferri's superb long-range strike early in the second half, but that would prove the lone bright spot for Lyon as Evian secured a deserved first win of the season to move off the foot of the Ligue 1 table.
Goals were in short supply elsewhere on Saturday, with Rennes playing out a 0-0 draw with Lille, while Sochaux's home clash with Ajaccio and Reims against Nantes also ended 0-0.
Cameroon striker Vincent Aboubakar scored against his former club Valenciennes in a 1-0 home win for Lorient, while ten-man Bastia triumphed 2-1 over Toulouse in Corsica. Despite Julian Palmieri's 36th-minute dismissal, Bastia took the lead just before the break through Romanian forward Claudiu Keseru.
Dane Martin Braithwaite then hauled Toulouse level on 57 minutes but Ivorian midfielder Romaric's first goal for his new club secured Bastia all three points. On Sunday, Saint-Etienne and Nice will be looking to put their UEFA Europa League exits behind them when they host Bordeaux and Montpellier respectively before Marseille meet Monaco.