RB Leipzig’s meteoric rise from the fifth tier to UEFA Champions League qualification inside just eight years caught the attention of the footballing world, including that of German juggernaut Bayern Munich, who saw a new rival quickly appear on the horizon.
Few teams have been able to keep pace with Bayern down the years in the Bundesliga. Borussia Mönchengladbach did it during the 1970s, Hamburg managed it for parts of the 80s and, more recently, Borussia Dortmund have regularly challenged the imperious authority of the Munich giants.
Leipzig, though, came equipped to push the record champions from the very start and for the foreseeable future.
Bayern and Leipzig meet as the top two for the second time this season, but on this occasion the roles are reversed at the Allianz Arena after the champions reclaimed first place on Matchday 20 for the first time since October.
It’s become a common configuration in clashes between the title rivals, and it all began back in December 2016 when Leipzig paid their first visit to Munich to take on the champions.
The Saxony club had just completed their seven-year climb from the fifth tier to the Bundesliga and arrived in Bavaria not just as top-flight newcomers, but level on points with Bayern at the top of the table in the final game before the winter break.
“We're going there to win,” proclaimed Leipzig's then sporting director Ralf Rangnick.
Watch: Leipzig were blown away on their first visit to Bayern
His prediction that Leipzig emulating Kaiserslautern and winning the title as a promoted club was "unlikely" proved accurate. Bayern’s statement 3-0 win opened up a three-point gap that eventually grew to 15 come the end of the season, but with Leipzig finishing second only to the Bavarians, they had already delivered a statement of their own.
That final difference could have been just nine points had the Red Bulls not squandered leads of 3-1 and 4-2 in their first-ever home meeting with Bayern on the penultimate day of the season, eventually going down 5-4 to the already-crowned champions.
It was the same scoreline, albeit on penalty kicks, when Bayern beat Leipzig in the second round of the 2017/18 DFB Cup. It set out the stall for guaranteed drama when these two teams meet.
Watch: Leipzig and Bayern produced an incredible nine-goal thriller in 2016/17
And they did so again just three days later in the first Bundesliga meeting of the season. It proved a rather simple three points in the end for the champions under Jupp Heynckes as they ran out 2-0 winners at home, with Leipzig finishing with 10 men for the third time in four encounters. James Rodriguez and Robert Lewandowski wrapped up the points after an early red card for Willi Orban.
A watershed moment followed in March 2018, though, as Ralph Hasenhüttl’s side recorded their first victory over the runaway league leaders. Despite displaying symptoms of the dreaded ‘second-season syndrome’ and ultimately finishing sixth – a whole 31 points behind Bayern – Leipzig still managed to come from behind to claim a 2-1 win at the Red Bull Arena thanks to substitute Timo Werner. Leipzig knew they could in fact beat Bayern, even in one of their most dominant campaigns for years.
Watch: Leipzig's only win against Bayern to date
It has seen the on-field differences reduce and the results become even closer. The record champions needed a late strike from substitute Franck Ribery for a 1-0 win in Munich before a goalless draw of attrition in Leipzig. Although nine points off their opponents on the penultimate matchday, the Red Bulls will have seen it as a feather in their cap that they delayed Bayern’s title win until the final day.
The world was then offered a taster for the coming title fights in the final of the DFB Cup in May.
For Bayern it was a chance to reassert their domestic dominance by claiming the double and a 19th cup title. For Leipzig it was a chance to show the footballing world that they meant business with a first major honour, and doing it against Germany’s best team.
In the end, 3-0 perhaps flattered Bayern but it was a typically professional job from a team that has proven time and time again that they know how to win. That is where Leipzig want to be and they are making progress.
Just a few days after that defeat in Berlin, Julian Nagelsmann, who had already been announced as the new Leipzig boss earlier in the season, took up his position at the Red Bull Arena. The youngest coach in the Bundesliga is also one of the most highly regarded and he arrived with the directive to win trophies.
It’s not a case of Leipzig looking to, to paraphrase Sir Alex Ferguson, knock Bayern off their perch, but to compete at the same level as the most successful club in Germany.
Further proof of the narrowing gap has been seen this season, too. Nagelsmann’s first match in charge of Leipzig against Bayern on Matchday 4 produced a fascinating spectacle. Lewandowski’s early goal was the result of a defensive mistake and the hosts were lucky to be level at half-time when Emil Forsberg converted a penalty after a dominant first 45 minutes by the champions.
Nagelsmann, though, showed he’s never afraid to react and made changes at the break. Leipzig performed much better and in the end deserved to keep their two-point early-season lead over the champions.
Watch: A tactical analysis of Leipzig's 1-1 draw with Bayern
Prior to Bayern moving back to the top of the league on Matchday 20, Leipzig had been above the champions in the table for all but four weeks. They know that the chances are they will win the league if they finish above the Munich giants.
They also know that a win at the Allianz Arena on Matchday 21, something neither they nor Nagelsmann have never done before against Bayern, would lay down the ultimate marker. Perhaps it would also knock down that final mental barrier.
Leipzig also have their own answer to goalscorer Lewandowski in Germany international Werner, while goalkeeper Peter Gulacsi has proven just as safe a pair of hands as Manuel Neuer. As squads, they appear evenly matched.
Watch: A closer look at how Werner is scoring so many goals
With over 70 pieces of silverware displayed proudly in their club museum, though, history is overwhelmingly in Bayern’s favour. But for Leipzig it seems only a matter of time before they’ll have a trophy of their own to parade. Everything at the club, from the players to the coach, is geared towards the future, and they’ve caught Bayern in transition.
Is it now or never for the Red Bulls? No, it looks like now and forever as they start to pose a permanent threat to Bayern’s dominance in a way that few others have done before. They have learnt from every defeat and grown into their role of leading challengers.
Expect Bayern Munich vs. RB Leipzig to be a defining fixture in the Bundesliga for years to come.