PSG had opened up a seven-point lead over the champions with a 5-0 win away to Angers in the day's early kickoff, but Monaco went one better to keep their star-studded rivals in sight.
The points were wrapped up before half time as Guido Carrillo, Adama Traore, Balde Keita and Fabinho sent the hosts into the break with a commanding lead, before Traore and Carrillo both doubled their tallies in quick succession in the final 15 minutes.
It took just 10 minutes for the hosts to break the deadlock when Almamy Toure raced down the right flank before swinging a cross into the middle which Carrillo met with a fine header into the corner.
Toure was proving to be a menace down the wing and he provided the second goal for Monaco too, flicking the ball over the head of Franck Tabanou inside the penalty area before laying it back for Traore to sweep home.
Two quickly became three as Monaco all but killed off the contest with nine minutes still remaining in the first half when Rony Lopes broke into the box and laid the ball on a plate for Keita, who could not miss into an empty net.
There was still time for a fourth before the half-time break too, with Carrillo being brought down inside the area and Fabinho tucking the subsequent penalty beyond Karl Johnsson, despite the Guingamp keeper guessing the right way.
The visitors did at least stem the tide in the second half, but Monaco were back on the scoresheet with just under 15 minutes remaining when Traore got his second of the night, although Johnsson should have done better as the ball squirmed under his arm before bobbling over the line.
Not content with their five-star showing, Monaco quickly added a sixth within two minutes as Carrillo scored another header, this time latching on to Rachid Ghezzal's delivery to power his finish home.
The proved to be the last of the scoring as Guingamp avoid any further humiliation, with the defeat seeing them drop a place to 13th, still only four points clear of the relegation zone.