Just two games into their campaign for an inevitable fifth consecutive title, Ronny Deila’s side illustrated the gulf which exists between them and the rest of Scottish football with an utterly comprehensive and facile victory at Firhill.
Amid their major challenge of trying to reach the group stage of the Champions League, Celtic were barely required to break sweat as they swatted their outclassed Glasgow neighbours aside.
The final scoreline does not begin to tell the story of their superiority on an afternoon when their goalkeeper Craig Gordon made his only save two minutes from time.
It was a day to remember for Australian international Tom Rogic, the injury-troubled 22-year-old midfielder marking his first starting appearance since September 2013 by netting his first goal for the club.
Kris Commons doubled the lead during a match in which Celtic might have threatened double figures had they been more clinical in front of goal.
Their domination of possession was absolute from the opening stages with not the slightest hint of fatigue from their midweek Champions League exertions in Baku.
Thistle could barely get out of their own half of the pitch and on the rare occasions they did manage to get on the ball, they were quickly pressed and harried out of it by the eager visitors.
The absence of injured captain Scott Brown did nothing to diminish the energy levels of Deila’s side in midfield, where Stefan Johansen dropped back to fill his role alongside Nir Bitton, with Rogic deployed in the more advanced position.
The only mild criticism of Celtic’s performance would be that it took them as long as it did to make the breakthrough, such was the regularity of clear-cut chances they carved out.
Leigh Griffiths should have put them in front after just 90 seconds, heading over from close range after being picked out by a perfect Emilio Izaguirre cross from the left.
It was a tough examination for Thistle’s youthful central defensive partnership of 19-year-old Liam Lindsay and 20-year-old Jack Hendry, pitched in against the champions because of Frederic Frans’ suspension.
They should have been punished in the sixth minute when a clever through ball by Johansen caught them flat-footed and found Stuart Armstrong unmarked inside the penalty area, but the Celtic midfielder’s first touch was poor and the opportunity slipped by.
Thistle goalkeeper Tomas Cerny was called into action for the first time a minute later, getting down well to hold a low shot by Commons. It was a busy afternoon for Cerny, who next showed good positioning to clutch a well-struck Griffiths free-kick.
Celtic were forced to make a change after just 20 minutes, Armstrong giving way to Callum McGregor, but it did nothing to disrupt their attacking momentum.
Another fine cross by Izaguirre, rampaging down the left at will, presented Griffiths with a close-range shooting opportunity but he was denied by Cerny’s excellent reaction save.
The Czech goalkeeper could do nothing but watch in relief a few seconds later, however, when a thunderous 25- yard shot by Virgil van Dijk smashed off the outside of his right-hand post.
Rogic then fizzed a shot narrowly off target before the weight of Celtic’s pressure finally paid off with his 28th minute opener.
McGregor, making his first appearance since February, delivered a good cross from the left which Griffiths knocked back into the path of Rogic. The big Australian displayed good improvisation as the ball bounced high in front of him, flicking it with the outside of his right boot beyond the helpless Cerny.
Thistle were struggling to lay a glove on Celtic and the notion that Scottish football is now simply too easy for Van Dijk was given a little more credence when the Dutch defender, strolling forward whenever he pleased to join the attack, left Lindsay bewildered with a delightful nutmeg before driving a shot just wide.
In the final few minutes of the first half, Celtic’s intensity levels dropped for the first time and Thistle felt they should have had the chance to level from the spot when a David Wilson cross struck Mikael Lustig on the arm. It was clearly accidental, however, and properly judged that way by referee John Beaton.
While they trailed by a single goal, hope at least remained for the hosts. Alan Archibald made his first change five minutes into the second half, new signing Mathias Pogba making his debut as he replaced Steven Lawless.
The elder brother of Juventus star Paul Pogba, the Guinean international gave Thistle added presence up front but their problem remained making any kind of telling progress towards Gordon’s goal.
Celtic, while they may have dropped down the gears in comparison to their first-half display, were still in control of proceedings and they claimed the cushion of a second goal in the 63rd minute.
Bitton’s long ball caught out the Thistle defence, allowing Commons to nip in ahead of Callum Booth and coolly chip the ball over the advancing Cerny into the net. Thistle showed spirit in the closing stages, Pogba finally calling Gordon into action with a low shot comfortably held by the Scotland international, but in truth they had to succumb meekly to a 17th successive league defeat in this fixture.
Partick: Cerny; Miller, Hendry, Lindsay, Booth; Osman, Welsh (Fraser 75); Lawless (Pogba 50), Wilson, Bannigan; Stevenson (Amoo 66). Subs not used: Scully, Seaborne, Doolan, McDaid.
Celtic: Gordon; Lustig, Boyata, Van Dijk, Izaguirre; Johansen, Bitton; Commons (Henderson 87), Rogic (Mackay-Steven 64), Armstrong (McGregor 20); Griffiths. Subs not used: Bailly, Ambrose, Scepovic, Janko.