Having been commanding on day one at Hibernian, they embarked on four consecutive friendlies and that seemed to dull their finishing when it came to the business of putting away Aberdeen.
Only after blasting efforts high and wide of goal for most of this brisk match did they finally manage to put one on target and past goalkeeper David Gonzalez.
The winning goal from Anthony Stokes came after a mistake by Richard Foster 17 minutes from the end. That rewarded a Celtic performance which was blunt but unmistakably dominant.
They have six points after two awkward away matches but the day was certain to be disfigured for them regardless of the result. Their Scottish player of the year, Emilio Izaguirre, suffered a broken leg after only a quarter of an hour.
Peter Pawlett slid in to hook away the ball from the left-back after one of his characteristic runs to the other end of the pitch. The tackle was fair, but the wee Honduran went down in a heap. The injury immediately looked serious and he could be out for three months.
Neil Lennon may look to sign another left-back. Yesterday Izaguirre was replaced by Charlie Mulgrew, who was booed by the home support for previously leaving them to join Celtic.
Foster was in danger of being jeered by everyone, given where he spent last season. Instead, when Celtic fans abused him for being an ex-Rangers man, the Aberdeen fans responded by cheering him. By the end, after he had made the error his manager called “suicidal”, there was a danger of those views being reversed.
Aberdeen have taken only one point from the first available nine and they have yet to score a goal. It was asking a lot of them to cope with Celtic when they didn’t have Youl Mawene holding together the back four, or Fraser Fyvie, Chris Clark and Ryan Jack across midfield. Generally they competed well, with little to show for it.
Celtic’s main absentees were Scott Brown and Mark Wilson, but they have the depth to render that irrelevant. Adam Matthews came in to deliver a bright display on his competitive debut. Lennon’s team as a whole was quickly into a rhythm and dominated large spells of the play, moving smoothly until it came to the final pass, cross or shot. Stokes, Gary Hooper and Kris Commons were often frustrated figures.
Pittodrie was dreich and damp. Celtic’s quick, pass-and-move style was easy on the eye and they comfortably knocked around the ball, stretching Aberdeen’s midfield and putting their defence on the back foot. Rob Milsom and Isaac Osbourne had to graft just to keep a toehold in the game, although both were under such pressure they often gave the ball away.
For all the pressure Celtic exerted, they never found their range. Commons tried a few shots but they always lacked either power or accuracy. Mulgrew had a free kick just where he likes them, but blasted a poor effort high into the Merkland Stand. Their final passes didn’t find a man or were cut out by Aberdeen’s reasonably solid defence.
At the other end, Darren Mackie had the pace to worry Daniel Majstorovic but not Kelvin Wilson, who again looked assured and quick. Only when Mackie and Scott Vernon opened up Celtic at the end of the first half was Lukasz Zaluska asked to produce a lively save. They came closest when Mackie delivered a low ball to the near post but Vernon failed to connect with it after shaping himself as if to score.
Some time will have to pass before Aberdeen go into a game against Celtic without feeling haunted by that 9-0 defeat at Parkhead last November. Only as the minutes ticked by without a goal did their confidence grow in this one. They had a better second half and held the ball a little longer.
At the back they are daring to hope that they have found a goalkeeper. Gonzalez was on the cover of the match programme, like a male model whose picture had been air-brushed.
The on-loan Manchester City man showed he has more to him than that. He was a steadying presence and dealt with what came at him. When Hooper raced through, Gonzalez took him on in a tackle, having the confidence to do a little drag-back to get away.
Aberdeen began to suspect they would escape defeat, but no. Foster was taking the ball out of defence but took too long to decide what he wanted do with it. Commons surprised him, putting in a tackle to win the ball to ignite a Celtic attack.
Aberdeen were exposed and for once Celtic’s execution was crisp: Commons cut back the ball for Stokes to ram in an easy finish.
It was an awful moment for Foster, the captain. Hooper might have taken some of the heat off him if he had scored a later chance, but Gonzalez got his body in the way. Lennon offered a consoling pat on the back as they passed each other at full-time. For the Celtic manager, though, thoughts soon turned to his own wounded man.