Brendan Rodgers' men sit second in the table of the new-look format for Europe's elite competition - behind only Bayern Munich - after thrashing Slovan Bratislava 5-1 on matchday one.
That was the first time in 13 attempts that the Hoops had won their Champions League opener. Confidence is high despite facing a huge step up in the calibre of opposition against last season's finalists.
Saturday's 6-0 demolition of St. Johnstone maintained the Scottish champions' 100 per cent record in all competitions this season.
In eight consecutive wins they have plundered 33 goals. But the signs of something special brewing were apparent even in pre-season as Celtic beat Manchester City 4-3 and Chelsea 4-1 during a tour to the United States.
Into the second season of his second spell in charge, former Liverpool boss Rodgers is primed to finally make a mark in Europe with Celtic.
The Glasgow giants have become accustomed to domestic dominance, winning 12 Scottish league titles in 13 years. That has not translated into progress on the continent.
Celtic's last run beyond the group stages of the Champions League was back in 2012/13. They have not won a knockout tie in any European competition outside of qualifiers in 20 years.
Even before the beating of Bratislava, Rodgers declared this is the "best prepared" he has felt as a Celtic manager for the demands of the Champions League.
'It's a dream'
Twice the club broke their transfer record in the final days of the transfer window to bring in Belgium midfielder Arne Engels and Irish striker Adam Idah - who both scored against the Slovakian champions.
Celtic are also still feeling the benefit from Tottenham boss Ange Postecoglou's recruitment during his two years in Scotland.
Japan trio Kyogo Furuhashi, Daizen Maeda and Reo Hatate, who shone against Bratislava, were brought to Celtic Park by the Australian after his time in charge of Yokohama Marinos.
"We know we can go there with real confidence," said Rodgers of the trip to the Westfalenstadion.
"It's a dream and they can live it. We're going to a great stadium and we're going to go there to show all the qualities that will hopefully give us an opportunity to get the result."
Dortmund also made a winning Champions League start thanks to three late goals to beat Club Brugge 3-0.
There are chinks in the armour of the German giants for Rodgers' side to exploit.
Dortmund were thrashed 5-1 by Stuttgart earlier this month and needed to come from 2-0 down to beat lowly Bochum 4-2 at home on Friday.
"There's no reason why we can't go and see where our football is at compared to these teams," said Celtic captain Callum McGregor.
Adding to the optimism fostered by Celtic's performances this season is the combination of a kind draw and a new format that offers the chance of progression.
RB Leipzig, Brugge and Young Boys are still to visit Celtic Park with seven more points likely to be enough to secure a place in the playoffs by finishing in the top 24 of the 36-team league.
Trips to Dortmund, Atalanta and Aston Villa look more daunting, but a visit to Dinamo Zagreb in December also offers the chance to pick up points on the road.
