Saturday May 20 marked 70 years since Celtic lifted the Coronation Cup.

It's just as well the Hoops have already been crowned Scottish Premiership champions or else the fans would be having heart palpitations along the way as their heroes put them through the emotional wringer once again.

What a time in the season for lethargy to strike Ange Postecoglou's men. That's two games now and five dropped points against Rangers and St Mirren, respectively.

It does nothing for Celtic in terms of building momentum ahead of their tilt at a world record eighth domestic treble in the Scottish Cup final on June 3 against Inverness Caledonian Thistle.

You get the feeling that Billy Dodds is sitting somewhere with copies of Celtic's last two matches and that he will play them on repeat to his Highland charges while telling them that miracles can happen.

While there is no need for widespread panic in the ranks, the last two performances should act as a wake-up call.

All of a sudden, at the back, when you take away the presence of players like Cameron Carter-Vickers and Alistair Johnston, Celtic seem to struggle. How St Mirren striker Curtis Main never helped himself to a hat-trick in the 2-2 draw with St Mirren at Celtic Park at the weekend is a minor miracle.

Carl Starfelt was arguably Celtic's best player in the 3-0 defeat at Ibrox but that's no barometer of success as Yuki Kobayashi had a day to forget in Govan. Fast forward seven days and Tomoki Iwata was paired with Starfelt as Postecoglou experimented with his central defensive backline again.

The Swede seemed spooked by Iwata's presence at the back and Main gave both men the runaround. Anthony Ralston didn't exactly cover himself in glory either as the right-back looked every inch the back-up player to the main attraction that is Johnston.

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Stephen Robinson's side have been worthy adversaries of Celtic and taken four points from them this season. Alongside Rangers, they have taken more off the Hoops than any other Premiership side this campaign.

As Postecoglou duly noted at full-time: "You have to credit St Mirren and they worked hard and we knew they would and it was a tough game for us.

"We were not at our best in terms of working hard enough and putting things into our play that allows us to dominate a game.

"The boys fought back and at least we got a share of the points. We never really got going. We lacked a bit of urgency and energy, particularly without the ball.

"We have been really good without the ball but we have just slipped off it in the last couple of weeks and when you do that it's hard to take control of the game with the ball as well.

"The way we set up is to try and put pressure on our opponents and we didn't do that."

Arguably, barring a scintillating first 45 minutes at Rugby Park during a 4-1 win back in April, Celtic have not really hit the heights that the players, the manager and their supporters have been accustomed to since defeating Hearts 3-0 in the Scottish Cup quarter-final at Tynecastle on March 11.

Maybe the exertions of such a long season and striving to be better than the last campaign are finally taking their toll on this group of players. After all, Postecoglou has consistently gone to the well and asked his team to drink from it and they have imbibed copiously and produced for him constantly.

Celtic Way:

"They are human beings, mate, not robots," the 57-year-old once opined and that's evident.

It is human nature to take your foot off the gas when titles and cups have been won but it's certainly not easy to press it back on the accelerator and revert back to normality after this.

On a positive note against the Saints, Kyogo Furuhashi made it 31 goals for the season and Callum McGregor somehow dredged a point out of the fire when all hope looked lost as Postecoglou's side kept up their incredible record of never having lost a domestic match at Parkhead since he took charge.

The Australian has two checklist boxes - performance and result - and Celtic have ticked neither of those boxes in their last two games. He will be hoping and praying it is just a  hiccup.

It is inconceivable to think that there will be any result other than a Celtic victory at Hampden Park on June 3.

However, one would conjecture that John Barnes in 2000, Martin O'Neill in 2003 and Ronny Deila in 2015 all thought exactly the same before facing Inverness in the Scottish Cup.

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Celtic have three games left to finish the season with a flourish. Technically one of them is all that really matters and that is the Scottish Cup final, where a potential world record eighth treble awaits. A chance to achieve something really special that will go down in the annals of history.

However, every passing Celtic performance of late should offer the Highlanders a glimmer of hope. The champions need to start ticking those performance and result boxes again, starting in the next match against Hibs at Easter Road.

In 1953 as the famous Coronation Cup song goes:

"The Celts beat the Gunners and Manchester too. Beat Hibs in the final and oh, what a scene, sure Hampden was covered in banners of green.

"Too-ra-loo, Too-ra-lay. Oh, the Celtic supporters were shouting that day!"

What's the 'Dodds' on lighting striking four times?

70 years on from that Coronation Cup triumph the chances of Hampden not being covered in banners of green come June 3 are still very remote.

Too-ra-loo!