Celtic ended a week they started four points clear at the top of the Scottish Premier League with a colossal 17-point advantage after a 5-0 win away to Hibernian on Sunday.
Second-placed Rangers' ten point penalty for going into administration, and subsequent 1-0 loss at home to Kilmarnock yesterday, had left Celtic in a strong position even before kick-off at Easter Road.
But Gary Hooper's double, as well as goals from Anthony Stokes, Charlie Mulgrew and substitute Ki Sung-Yueng saw Celtic pile on the agony for both arch-rivals Rangers and, indeed, second-bottom Hibernian.
Stokes headed Celtic into a 14th-minute lead against his former club when he was first to Mulgrew's inswinging cross. Just six minutes later Celtic were 2-0 in front when, after Stokes had beaten three defenders, the unmarked Hooper scored the first of his two goals.
Only two minutes had passed in the second half when Mulgrew added a third goal, with a curling free-kick from more than 20 yards out.
Another long-range shot, this time from Hooper, bounced over goalkeeper Graham Stack's arms to make it 4-0 before Kris Commons's drive deflected off fellow substitute Ki to complete the scoring 13 minutes from time.
Earlier, St Johnstone missed the chance to go fourth after sharing the points in a goalless draw away to Aberdeen at Pittodrie in the day's other Scottish top-flight match.