The Scottish champions had been soundly beaten 6-1 on aggregate by Legia Warsaw in the previous qualifying round, but were given a reprieve when Warsaw fielded an ineligible player in the second leg.

UEFA kicked them out of the competition and Celtic were allowed to take their place in the final qualifying round against Slovenian champions Maribor.

After a decent 1-1 draw in the first leg, with an away goal and the booming Celtic Park atmosphere, pundits and fans alike were expecting to see Celtic in the Champions League group stage draw later this week.

But what transpired was a poor display in which Celtic had less possession than their opponents and only 2 shots on target all game. That would have been all well and good with their away goal, had Maribor not then grabbed a vital goal in the 75th minute.

Having failed to create any real chances, Celtic were left with 15 minutes to salvage their Champions League season, but they could not.

With the £14m loss of revenue and the lure of playing in Europe's premier competition, manager Ronny Deila has admitted it will be difficult to sign the right players.

So the question is now, what next for Celtic, and what next for Ronny Deila?

They have dominated the top flight of Scottish football for several years since their arch rivals Rangers were relegated, and have started with two wins and a loss from their opening three league fixtures. 

A solid start then, with an already healthy goal difference of +7, but with the league having been a walkover for Celtic for years, anything but total domination would be unthinkable for Celtic fans.

The Scottish Premier League does not have the quality that it's counterpart south of the border has, that is no great secret, and with the resources and stature Celtic have, the idea of being run close by anyone else in the league, even if they do win it, is not something most associated with Celtic are willing to entertain.

The tie against Warsaw raised some serious questions about the team's credentials, despite their eventual reprieve, and entry into the Europa League will raise mixed emotions.

On the one hand, with the lower quality of opposition, Celtic would be expected to at least get through the groups, if not make a sustained push to the latter knock out stages. 

The chance for success is higher, but winning the whole tournament, with the level of opposition that drops in from the Champions League after the group stages, would be a big ask.

The other side of the coin, besides the huge loss of revenue the Champions League brings, is that when fans have nights of beating Barcelona fresh in the memory, will they really be geared up for the facing Champions of Romania, or Belgium, or Austria?

Having visited the Nou Camp and the San Siro last season, are Celtic's faithful away contingent going to be willing to travel to the far reaches of Europe on a Thursday night?

The catch 22 for Deila is that although the anticipation for the Europa League is lower, the expectations are higher. The fans might see it as a lesser competition but they will still want to do well in it.

Domestically Celtic will almost certainly assert their authority over the course of the season, but with that now seen as a given, at least until their rivals Rangers are back in top flight, what can Deila do to prove he's the right man to take Celtic forward?