THERE were many factors which led to the departure of Ronny Deila from Celtic last season; his signings being unable to make an impact, a frustrating reliance on a 4-2-3-1 formation and the humiliating defeats his side suffered both at home and abroad all contributed to his demise as manager.

Yet, the Norwegian’s failure to steer the Parkhead club into the group stages of the Champions League during his time in Scotland was something which many supporters were unable to accept or forgive.

READ MORE: O'Connell appeals to Celtic boss Rodgers to hand him Champions League start in Astana

If Brendan Rodgers, then, is to justify the widespread euphoria which greeted his appointment this summer and prove a success in Glasgow it is vital he does well where his predecessor was found wanting in Europe’s premier club competition.

Beating a Rangers team strengthened by the arrival of, among others, Joey Barton, Clint Hill and Niko Kranjcar, to the Ladbrokes Premiership title in the 2016/17 campaign and winning the Betfred Cup and William Scottish Cup will certainly endear him to his new employers and their legion of followers.

Celtic fans, though, have grown accustomed to seeing their team take on, and often beat, the continent’s elite in modern times. It is three long years now since the strains of Zadoc the Priest, the Champions League anthem, have been heard in the East End. That is far too long for many.

But is it really reasonable to demand that the Scottish champions secure a place alongside the likes of Barcelona, Bayern Munich and Benfica under Rodgers this season?

He has, it must be remembered, had little more than a month to work with his squad on the training field. He has had just a handful of friendlies and two competitive fixtures, against semi-professional opponents, ahead of the first leg of the third qualifying round against Astana, a team which drew with Atletico Madrid, Benfica and Galatasaray last season, in Kazakhstan this week.

The signing of Kolo Toure, the former Arsenal, Liverpool and Manchester City defender, at the weekend was only his second since taking charge and the Ivory Coast internationalist won't be added to his squad for the Astana game as a wildcard. Rodgers is painfully short at the back. It is far from ideal preparation.

READ MORE: O'Connell appeals to Celtic boss Rodgers to hand him Champions League start in Astana

Gordon Strachan and Neil Lennon enjoyed some memorable nights in the Champions League during their stints in charge of Celtic. They each secured qualification – twice in the case of the former – for the knockout rounds. But it shouldn't be forgotten that both men endured acute disappointment in their early outings.

Strachan famously suffered a 5-1 loss to Artmedia Bratislava of Slovakia. Lennon, meanwhile, was unable to get the better of Portuguese opponents Braga. It was only in their third seasons, after they had been given time to settle into their roles, learn from their mistakes and build a team capable of competing, that they flourished. Why should Rodgers not expect the same luxury?

The Irishman is, however, in a different position. He is, after spells in charge at both Swansea City and Liverpool in the Barclays Premier League in England, a far more experienced coach than both Deila and Lennon were when they took over. That is reflected in the handsome remuneration package he has been given.

Rodgers has a far lengthier track record on the continent as a manager than even Strachan had. The Scot had only been in the dugout for a paltry two games, against Steau Bucharest in the UEFA Cup with Southampton, when he arrived.

The current incumbent has three Europa League campaigns, two of which he took his team into the last 32 in, and one season in the Champions League group stages with Liverpool behind him.

He can also take advantage of the champions route to the group stages. It was introduced by Michel Platini, the former UEFA president, seven years ago to allow the champions of smaller footballing nations to qualify. If Astana can be dealt with then the team Celtic will be drawn to face in the play-off will be eminently beatable. The likes of Manchester City, Porto and Roma, who will go through the league route, will all be avoided.

The squad he inherited from Deila is also strong. If anything, he has too many players. He may, with Dedryck Boyata out injured and Jozo Simunovic a long-term absentee, be lacking centre backs. But he has an abundance of options in other areas and certainly has goals in his side.

READ MORE: O'Connell appeals to Celtic boss Rodgers to hand him Champions League start in Astana

Defeat to Astana or in the next round will by no means spell the end for Rodgers. Far from it. The Celtic hierarchy always give their managers the time and backing they need to deliver success domestically and in Europe.

But getting into the Champions League this season would be a hugely significant achievement and would ingratiate him greatly to supporters with high expectations.