WHAT a difference the past fortnight has made for Celtic.

This time two weeks ago the ultras element of the Glasgow club’s support was finalising plans for an anti-board protest outside Parkhead following painful back-to-back defeats.

Ange Postecoglou’s team had been knocked out of the Champions League by Midtjylland of Denmark and been beaten by Hearts at Tynecastle in their opening cinch Premiership fixture.

It was too much for some of their fans to take after the miserable failure of their 10-In-A-Row bid last season – and that unhappiness was understandable to an extent.

Postecoglou had to field youngsters Anthony Ralston, Stephen Welsh and Dane Murray in defence in Denmark and his charges missed out on a lucrative place in the group stages of Europe’s premier club competition for the fourth year running.

The Greek-Australian coach should have had far more options available to him heading into a game with so much riding on it both financially and reputationally.

But comfortable triumphs over Jablonec in Europa League qualifying as well as convincing wins over Dundee in the Premiership and Hearts in the Premier Sports Cup in August have completely transformed the mood in the East End.

Now there is widespread elation at the football that Celtic, who have scored 16 times in their last four outings, are producing and excited chatter about their future prospects.

With Rangers losing both home and away to Malmo in the Champions League and also being beaten by Dundee United in their second league game at Tannadice, hopes are high they can challenge strongly for the Scottish title and other honours.

So can Celtic, who finished 25 points behind their city rivals in the top flight, performed poorly in the cup competitions and ended up trophyless last term, reclaim their place as the dominant force in the country in the coming months?

It is early days for Postecoglou and his new-look squad and it would be wrong to make wild predictions on the evidence of four wins against limited rivals. Still, the signs are certainly encouraging.

His players appear to have responded well to his coaching and fully embraced the radical tactical changes he has implemented.

The aforementioned Ralston has only been given an extended run in the first team due to the complete lack of options at right back. However, he has more than justified his inclusion in the starting line-up.

The excellent performances of the 22-year-old, who has scored twice, would suggest that his new manager is capable of instilling confidence in his players and also improving them as footballers.

Postecoglou, too, has signed well so far. His predecessor Neil Lennon suffered last term when Albian Ajeti, Vasilis Barkas and Shane Duffy, his big summer captures, failed to deliver. By Liel Abada, Kyogo Furuhashi and Joe Hart have impressed.

Furuhashi in particular. The Japanese internationalist has pace and ability. He was involved in the opening two goals in the  League Cup victory over Hearts on Sunday and then scored the third himself to take his tally to five in as many games. He looks to be £4.6m well spent.

Can James McCarthy, the Republic of Ireland internationalist who made his debut for his boyhood heroes when he came on in the second-half against Hearts, make the same sort of impact as Abada, Furuhashi and Hart?

If the defensive midfielder can then Celtic, who take on AZ Alkmaar of the Netherlands in the first leg of their Europa League play-off at home tomorrow evening, will be even more formidable opponents.

The new arrivals, though, are not the only ones who have flourished. Ryan Christie and Tom Rogic have both got their mojos back and then some. The latter was immense in the 3-2 triumph this weekend.

Had Craig Gordon not been in inspired form in goals for Robbie Neilson’s team then the margin of victory would have been far, far greater. The keeper’s old club were relentless and entertaining.

The bumper crowd enjoyed every minute of it and created quite an atmosphere. Having crowds back will help their cause too. Soulless and silent stadiums were a major contributing factor to their woes last season.

The goals that Celtic – who were porous at the back, at set pieces especially, at home and abroad last season – have conceded are something of a concern to their supporters.

Jablonec breached their rearguard twice in the Czech Republic and Hearts scored two in the second-half this weekend. It was all too familiar.

Carl Starfelt is adjusting to his new surroundings and Christopher Jullien has to come back from a long-term injury. But there is work still to be done there before they can challenge for silverware.

The same is true in the transfer market. Postecoglou demands a great deal of his players physically and Celtic play in so many games both domestically and on the continent. He needs quality back-up in every position to maintain the high tempo he desires and negotiate a packed schedule.  

Ajeti, McCarthy, Adam Montgomery and Ismaila Soro came on against Hearts. Nir Bitton and Leigh Griffiths remained on the bench. But when Callum McGregor and his team mates faded towards the end and made some careless errors it showed that reinforcements are still required.

“I keep saying it,” said Postecoglou afterwards. “We need more players to support the ones we have. Hopefully getting a few more players in will allow us to maintain the standard for 90 minutes.”

Christie, Odsonne Edouard and others could depart before the transfer window closes at the end of this month. If they do and no adequate replacements have arrived then it will undermine their revival and lead to problems down the line.

Rangers, who thrashed Dunfermline 5-0 at Ibrox in their cup tie on Friday night, will doubtless put their own early-season difficulties behind them in time even if they have to sell one or two prized assets to balance the books.

They went undefeated in the Premiership last season and reached the last 16 of the Europa League. They have not become a bad team overnight despite the hysterical overreaction to their recent poor form.

But the league game between the Glasgow giants at Ibrox on Sunday week will make for very interesting viewing and promises to be a far closer encounter than many of those between the age-old rivals were last term given how well resurgent Celtic are currently playing.