IT was all about the SAS for Celtic. 

Not Sutton and Shearer.

For those with a penchant for mathematics, they will be familiar with sequence and series.

Ange Postecoglou's prowess in this department may not have been fully disclosed to the Celtic faithful just yet but he's certainly methodical when it comes to his style of football management and playing philosophy.

The 3-2 Europa League group defeat to Bayer Leverkusen on Thursday night which consigned Celtic to the Europa Conference League had also brought their sequence of nine matches unbeaten in all competitions to a shuddering halt.

Ange and the Celtic players knew they had to get straight back on the domestic horse and prove their bouncebackability as they attempted to reel off another similar series of results as the Reds came calling to Glasgow.

Ironically for Ange and the bhoys it was the corresponding league fixture against Aberdeen at Pittodrie in October which had kick-started the recent impressive undefeated run.

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You didn't need an abacus, algorithms, calculators or even a slide rule to work out this arithmetical conundrum.

The formula for this particular operation was a very simple one.

Win the game equals another three priceless Scottish Premiership points banked for Celtic.

There were no other variables for Ange and his merry men especially after league leaders Rangers had defeated Livingston 3-1 earlier in the day in West Lothian.

The probability of Celtic racking up another precious home victory had greatly improved as they had taken 16 points from a possible 18 in their last six league encounters which was a win ratio of almost 89 per cent.

The statistics certainly favoured the men from Glasgow's East End as they entertained ​an Aberdeen side who had taken the square root of sod all in back-to-back league encounters but on their day Stephen Glass's side could also prove to be obtuse opponents.

However, there was also an added element thrown into the equation for good measure with former Captain, Leader, Legend Scott Brown marking his return to Paradise since leaving in the summer.

The last time Brown pitched up in Glasgow he scored a diving header at Ibrox against Rangers as the Dons drew 2-2. It was a moment the midfielder rather enjoyed.

A repeat of the trick would no doubt lead to Broony's once adoring public telling him to go forth and multiply.

There was also a special number in the hearts and minds of every Celtic supporter as "Wee Ten-Thirty" the Lisbon Lion legend Bertie Auld was remembered in his spiritual home after the famous number 10 had been laid to rest earlier this week.

There was a centre circle display bearing the words: "That's Entertainment", No.10 and YNWA" emblazoned across the famous green and white hoops as well as a plinth sporting the European Cup replica and Auld 10 underneath it.

Both skippers Callum McGregor and Scott Brown laid wreaths in an emotional tribute as a Bertie Auld inspired rendition of the 'Celtic Song' blared out over the PA system before a minutes applause to honour a wonderful character who will never be forgotten in the history of the club.

It was time to see if Celtic could in the immortal words of Auld "play and entertain" as Ange made two changes from the starting line-up that lost to Bayer Leverkusen.

Out went the injured Israeli midfielder Nir Bitton with Republic of Ireland star James McCarthy getting a rare chance to shine on a bitterly cold November day in Glasgow. James Forrest made way for Liel Abada as the Aussie shook things up in the attack.

Aberdeen made their intentions clear from the off when Christian Ramirez floored Joe Hart with a needless high challenge.

Hart recovered and got to his feet after a lengthy stoppage and then Jota was the victim of crude studs down the back of his Achilles tackle from Lewis Ferguson. It was a robust start for the visitors.

The Reds were undone by a piece of Celtic trigonometry though on 20 minutes. Bertie Auld would have been proud as it had entertainment and class stamped all over it.

David Turnbull lofted an exquisite pass into the path of Callum McGregor who took it down on his chest and calmly fed man of the moment Jota who sidefooted the ball high into the net for the opening goal to make it eight in 18 appearances.

Celtic Park was stunned into silence when Abada clumsily left his foot in on David Bates and referee Kevin Clancy awarded a penalty which Lewis Ferguson despatched with ease to restore parity on 33 minutes.

The spot-kick setback knocked the hosts off their stride and for the remainder of the half it was largely pedestrian and the stalemate remained at the break.

Celtic got their noses in front rather fortuitously on the hour mark.

McCarthy threaded a lovely pass through to Abada who could only hit the advancing Dons goalkeeper Joe Lewis but then Jonny Hayes got his angles all wrong and smashed the ball of McGregor's heel and it ricocheted into the back of the net and Celtic were 2-1 to the good. It proved to be the winner.

READ MORE: Celtic 2-1 Aberdeen: Bizarre Callum McGregor goal clinches Premiership win for Ange Postecoglou's side

Whilst Ralston saw a header superbly tipped over by Joe Lewis and Jota shaved the post, Celtic made it six wins out of seven in the league.

Ange will be hoping that this crucial Premiership win over Aberdeen is the start of a new sequence and series of winning results.

If Celtic are to remain within touching distance of Rangers and go the full nine yards in the title race then they will have to be content to match the champions stride for stride especially at this crucial juncture of the campaign.

That much is elementary.

It's most certainly not Pythagoras theorem.