Dortmund coach Jurgen Klopp
Klopp, 43, had been in line to coach Bayern in 2008, but the Bavarian giants opted instead for former Germany coach Jurgen Klinsmann, who was later sacked after only ten months in charge in April 2009.
Having taken over at Dortmund in July 2008, the former Mainz handler guided his side to top six finishes in both of the last two season's before they dominated the Bundesliga this year from October onwards.
Klopp's young side have grown in confidence throughout the season with a group from Dortmund breaking into the national side.
Defender Mats Hummels is a star of the future, while 18-year-old wunderkind Mario Goetze has already been earning the praise of pundits across the country.
While Klopp celebrates Bayern's hierarchy will be left thinking of what might have been.
"I was talked into trying the adventure with Klinsmann, but before that I already had a verbal agreement with Klopp," Bayern president Uli Hoeness admitted in an interview in January.
"I asked him to relieve me of the agreement when we had the idea of working with Klinsmann.
"That was a big mistake, as we know now."
Home and away wins over Bayern this season underlined Munich's mistake as Borussia beat the Bavarians 2-0 in Dortmund in October and then secured their first win in Munich since 1991.
Klopp's side, with an average age of just under 23, was the youngest Dortmund team to take the field and they ended the longest winless record in the club's history with 3-1 victory at Munich's Allianz Arena in February.
"The last time Dortmund won in Munich most of my players were still being breastfed," joked Klopp.
But he was not inaccurate: Goetze, who set up two of the three goals in Munich, had yet to be born in 1991 while goal-scorers Turkey midfielder Nuri Sahin and Hummels were not yet in Kindergarten.
Dortmund's bosses have moved to keep hold of Klopp for at least the next two seasons and he signed a contract extension last November to remain at Borussia until at least 2014.
"Jurgen Klopp is a symbol of the team's development, and not just this season," said Dortmund's director of sports Michael Zorc.
"He is a great asset and symbol for the club's brand."
Dortmund are in a rude state of health, both on and off the pitch.
They regularly sell out their 80,000-capacity stadium and in March revealed pre-tax earnings of 4.3 million euros for the first half of the fiscal year 2010/2011.
Having swept aside all before them in the Bundesliga, Dortmund have also extended the contracts of all their young stars.
In March, Germany centre-back Hummels, who joined from Bayern in January 2008, was signed up until the 2014 World Cup, when he could well be a first-choice in the national team.
The 22-year-old joined fellow Germany team-mates Marcel Schmelzer, Goetze and Kevin Grosskreutz on contracts until 2014, while Turkey midfielder Sahin is signed up until June 2013.
Real Madrid are reported to be interested in signing Sahin, but Klopp says any interest in his players from top teams shows how far Dortmund have come.
"We're not crazy, we are aware that with the type of football we play, our players attract attention," said Klopp.
"But we are in a position where we can decide whether or not to discuss a player's possible departure."
Short link: