Anthony Stokes scored in the 28th minute as Celtic downed St Johnstone, 1-0, on Thursday at Celtic Park in the Scottish Premier League.
Stokes scored the lone goal just inside the half-hour mark when he deposited a shot to the lower-left corner from six yards for his 14th goal.
Celtic made the goal stand up, as it posted its fifth straight shutout since a 3-2 loss to Rangers in late March.
The Bhoys reached 90 points for the season with three matches left to play. St Johnstone remained fifth in the table.