Clive Lindsay, BBC Sport Scotland
Brendan Rodgers had gone into the game against St Johnstone suggesting that his squad was weaker than the one that completed the treble last season under Ange Postecoglou.
His preparations had been disrupted further by injuries that led to Liam Scales being handed a first appearance since February 2022 in a new centre-back pairing with recent signing Gustaf Lagerbielke.
There was also a welcome first appearance since last season's Scottish Cup final for fit-again Canada right-back Alistair Johnston.
However, the reshaped defence was rarely tested by a St Johnstone side who, whether by design or lack of capability, rarely ventured out of their own half.
It was up front where Celtic looked pedestrian compared to the side that swept all before them domestically last season with their famed intensity and ability to pull apart tight defences under his Australian predecessor.
St Johnstone arrived on the back of what manager MacLean described as two weeks of "home truths", a "mini pre-season" and a clutch of new signings since a dismal defeat by Ross County.
Fielding three new loanees and with striker Luke Jephcott handed a first start up front, they were focused on simply surviving the Celtic Park experience.
Yet they came mightily close to inflicting Celtic's first domestic defeat since January 2021 and ending a 27-game wait for a win over the Glasgow side as they ended their own run of four straight losses to give a hint of better times ahead.