The Barcelona playmaker struck with a close-range finish in St Petersburg in the first minute of stoppage time, before the PSG forward added another just seconds before the end of the match.
The goals came after the underdogs had seemingly escaped with a draw after VAR rescued them from a penalty in the 78th minute when Neymar went to ground theatrically.
It means Tite’s men now top Group E on four points, ahead of Serbia, who face Switzerland later today.
Costa Rica are now out of the tournament.
