This was a day for new Celtic heroes, not least among them James Forrest, a young homegrown winger in the McGeady mould, who claimed their third of four goals against an outclassed St Mirren.
Joe Ledley put Celtic ahead on six minutes and when Shaun Maloney claimed a second before half-time with a deflected effort, the outcome was never in serious doubt.
Forrest's moment came after 68 minutes will be remembered by him, but the pick of the goals was still to come, Ki Sung-yueng's late hit from well outside the area taking the plaudits.
Celtic received £9.5million from Spartak Moscow for McGeady, but this was not to be an afternoon he was missed as Neil Lennon's new-look team turned on the style.
There was an irony about the final scoreline. It was a 4-0 defeat to St Mirren that saw Tony Mowbray removed as Celtic manager back in March.
Cha Du-ri failed a late fitness test on a hamstring injury to miss out for Celtic as they hosted St Mirren in their first Scottish Premier League home game of the season.
Jos Hooiveld, suspended for the European tie with Utrecht, returned in defence, while Forrest was afforded a start as Glenn Loovens missed out.
St Mirren's only fit forward was Craig Dargo so he began alone up front, the visitors unable to field their on-loan striker from Celtic, Paul McGowan, while Michael Higdon was banned.
Forrest had an immediate impact as he played a major part in Celtic taking a sixth minute lead, darting beyond two St Mirren defenders on the left flank before playing the ball infield.
His pass was collected by Georgios Samaras who slipped Ledley through and the summer signing from Cardiff produced a low driven finish for 1-0, shooting across Paul Gallacher in the St Mirren goal with the outside of his foot.
Samaras was proving difficult for St Mirren to track and he again found space to set up Marc-Antoine Fortune to cut inside and fire into the side-netting.
David Van Zanten collected a 15th minute booking for upending Forrest, though St Mirren did spurn a rare scoring chance when Darren McGregor's poor control prevented him getting a shot in before Lukasz Zaluska's diving block.
Celtic almost doubled their advantage in the 22nd minute when Samaras tapped the ball to Beram Kayal who produced a stunning shot from distance that bounced back off the angle of post and crossbar.
A minute later and it was 2-0, Fortune advancing down the right and from his low cross, Maloney was claiming the final touch, though the ball looked to have entered the net via a St Mirren defender with both John Potter and Van Zanten in the mix.
Celtic were the dominant force and only the woodwork was keeping the score down, first a fine Maloney strike struck Gallacher's left-hand post, while from the rebound, Fortune's effort hit the outside of the same upright.
Maloney, clearly lifted by his goal even if he may yet not get to keep it, was in confident mood and his trickery set up Samaras for what proved a wayward strike at goal.
St Mirren replaced the booked Van Zanten at half-time with another defender, Marc McAusland, as Danny Lennon tried to stem the Celtic tide.
The pattern of the game, though, was unchanged, first Brown shooting well from distance and then Gallacher being forced into a fine low save to keep out a Samaras strike.
Maloney sent in a dangerous free-kick that Hooiveld sent narrowly wide with a glancing header.
Celtic opted to withdraw Samaras to introduce the extra flair of Paddy McCourt, who scored the club's winner on the opening day at Inverness before being forced off after his celebrations left him with a whiplash injury suffered when he collided with Maloney.
Celtic made it 3-0 when Fortune set up Forrest whose powerful angled drive left Gallacher without a hope.
Lennon made more changes as he replaced the excellent Kayal with Ki , while Daryl Murphy replaced Fortune.
St Mirren were offering little in response, but Sean Lynch should still have done better as he could only manage a tame effort when the chance to shoot arose with Zaluska out of position.
Ki had enough time to leave his mark on the game with an outstanding fourth goal, leaving Gallacher motionless with a terrific long-range strike.