NK MARIBOR have not featured in the group stage of the Champions League since 1999.

It has not been for the lack of trying. This is the fourth season in succession in which the Slovenian champions have taken their place in the qualifying process only to fall short each time.

The hope is that this is the year when they finally make it over that last hurdle. Should they take care of Celtic over two legs this week and next, it would end a 15-year exile of Slovenian clubs from the group phase of the competition.

It would also mark the realisation of Zlatko Zahovic's seven-year plan. Maribor's director of football and Slovenia's most famous football export arrived at the club he supported as a boy in 2007 and has spent the subsequent period trying to build a team capable of earning a seat at European football's top table. It has been a painstaking process but they again stand on the brink of taking that final step.

Defeat in a 2010 Europa League play-off tie by Palermo - after beating Hibernian in the previous round - came with a sizeable consolation prize. So impressed were the Italians that they came back to sign three Maribor players, Josip Ilicic, Sinisa Andjelkovic and Armin Bacinovic. The collective sums raised helped clear the club's debt of around £10m and with the taxman finally off their backs, Maribor went on to win the next four league titles.

That has given them a path into Europe each season but so far it has been the group stage of the Europa rather than the Champions League that has been their annual destination. There is an acceptance among the Maribor support that, as the unseeded team, that will continue to be their level but they have not given up on returning to the Champions League one day, something that would be hailed locally as a "miracle" in a league where average attendances reach only the 800 mark.

Beating Rangers in 2011 took Maribor into the group phase of the Europa League for the first time, and in the two subsequent seasons, they have competed well in the Champions League qualifiers before falling just short. In 2012/13 they won their first two ties comfortably before falling to Dinamo Zagreb, their neighbours from Croatia. It was a blow to the national esteem, with the Slovenians desperate to show their old Yugsloslav comrades they are not just a nation of skiers. It was a similar tale last year. After knocking out APOEL just 16 months after the Cypriots had featured in the quarter-final of the competition, the play-off round again proved to be the final stop on Maribor's Champions League journey, with Viktoria Plzen of the Czech Republic too strong over two legs. Maribor, reeling from the departure of coach Darko Milanic and temporary exit of Zahovic, had again come up short.

The Europa League, though, has proved to be a decent fallback. Two seasons ago, they beat Panathinaikos at home, drew with Tottenham Hotspur, and were tying 1-1 at White Hart Lane in the reverse fixture before succumbing 3-1. They improved last year, drawing with Rubin Kazan in Russia, and beating Wigan Athletic and Zulte-Waregem, in Belgium, to set up a last-32 tie against Sevilla. Again they did not disgrace themselves, drawing 2-2 at home and going down only 2-1 in Spain to the eventual winners.

This season, they hope, will bring a return to the Champions League. Their performances this season - as well as a UEFA co-efficient greater than Legia Warsaw's - suggests Celtic should be wary ahead of the first-leg tie tomorrow night. Maribor are undefeated in four European matches so far this season, beating Zrinjski Mostar of Bosnia and Maccabi Tel-Aviv at home without conceding a goal, and drawing away.

Their transfer policy in recent years should sound familiar to Celtic fans. Asked whether he would strengthen his squad for this play-off tie, Zahovic's reply was as flamboyant as some of his moves as a player. "If Maribor was to buy player for €1m, the club would be finished," he said. "We will never buy experience. Maribor buys problems which, after two months, are no longer problems."

Expectation, therefore, is not unduly high in Slovenia ahead of this tie. Celtic's heavy loss to Legia came a surprise in a country where Scottish football is still held in relatively high esteem, a legacy of the national team's 3-0 win in 2005. "We have to be very humble," added Zahovic. "If we are then we have a chance. But for now I would rate our chances below 50%."