PSG wins 5-1 at defending champ Lille
It was a late reminder of Ben Arfa's remarkable but possibly wasted talent at 34 years old.
Grbic then made an incomprehensible blunder by failing to move for a corner and awkwardly allowing it to pass him by as centre back Presnel Kimpembe scored from close range.
On PSG's third goal, he was not at fault, but his defence was. It failed to clear the ball, allowing it to fall at Messi's feet.
Nice had earlier lost 1-0 at home to struggling Clermont to miss out on second place and an automatic Champions League berth.
Nice remained one point behind second-placed Marseille as winger Elbasan Rashani scored in the 77th minute for promoted Clermont.
Pereira's deflected strike flew past Grbic by chance in the 50th minute, but Kylian Mbappe's exquisite curler from 20 metres midway through the second half was anything from lucky.
"Perhaps some of the players were already thinking about Wednesday," Nice coach Christophe Galtier speculated. "You get punished if you don't respect your opponent."
Rennes, Stephan's former club, are still in fifth place after beating Brest 2-0 at home, with striker Gaetan Laborde and winger Martin Terrier scoring their 11th league goals.