Celtic continue their Europa League campaign on Thursday when they face RB Leipzig.
The Bundesliga big hitters are a formidable side, having quickly established themselves amongst the German game's elite.
Only formed in 2009, Leipzig have risen through the ranks at a rapid pace.
Their stunning surge to the top hasn't gone unnoticed, though, with contempt handed out to them over the years.
Until 2009, RB Leipzig was a lowly club in the fifth division called SSV Markranstädt.
But then Red Bull made their move, buying the club's licence, changing its name, crest and kit, and making it known their plan was to reach the top flight within ten years.
The drinks giant owns a number of teams named after the brand: Red Bull Brazil, Red Bull Salzburg and the New York Red Bulls.
But German laws prevent teams taking on the names of sponsors. As such, Red Bull opted to call their new investment RasenBallsport, which translates roughly as "lawnball", to circumvent the issue as best they could.
It's not the name which causes the real bone of contention for rival fans, though.
The German game deters billionaire investors from bankrolling teams, with laws ensuring club members control the majority of the shares in the entity that owns the team.
Borussia Dortmund, for instance, have more than 150,000 members. RB Leipzig, on the other hand, have just 17 members so while they follow the letter of the law, for many they don't follow its spirit.
This means from the start RB Leipzig have been met by vociferous opposition.
Some clubs refused to play them, fans boycotted games, after one match the players and coaching staff had to run straight to the bus, while before another their bus was blocked by supporters.
Last season someone threw the severed head of a bull onto the pitch.
RB have skipped over these hurdles, however, to reach the top. A huge investment drive from Red Bull has helped, as have a series of shrewd appointments.
Ralf Rangwick's arrival as sporting director in 2012 accelerated progress, with young stars, such as German international Joshua Kimmich, arriving and making their names at the club.
A spending spree once they reached the second tier resulted in Leipzig easing their way to the Bundesliga, where they made a splash on their debut season.
They were Bayern's closest challengers that time out, achieving Champions League football as a result.
While last campaign wasn't quite as fruitful, a sixth-placed finish did ensure European football for a second year on the trot.
Now, Leipzig are preparing for their next step, having announced talented young coach Julian Nagelsmann will switch from rivals Hoffenheim for next season.
Leipzig are a fast, attacking side, renowned for their ability on the counter-attack.
Blessed with real pace going forward, Celtic must beware the threat of German marksman Timo Werner, who led the line for his country at the World Cup after hitting the net with regularity for his club.
Portugal winger Bruma is a danger from wide areas, and comes into the match on form after recently scoring a stunner against Scotland at Hampden.
Swedish international Emil Forsberg and Austrian star Marcel Sabitzer pull the strings in the middle of the park, while powerful young defender Dayot Upamecano is a formidable presence at the back.