Dortmund are - along with RB Leipzig - the Bundesliga's form team. The Black-Yellows have taken 22 points from a possible 27 since the turn of the year, when they trailed Bayern by nine points.
Bayern, in contrast, have claimed 17 points across the same period, having lost to Borussia Mönchengladbach and Bochum, whilst being held to 1-1 draws by Bayer Leverkusen and Hoffenheim. If they slip up again at home to Union Berlin, and Dortmund win in Cologne on Matchday 27, Die Schwarzgelben could find themselves - in the best-case scenario - a point off the pace heading into the March international break.
Mathematically, the title race is very much on. Historically and - by extension - psychologically, there's a little more to it.
In the previous 58 seasons of Bundesliga football, the table leader at the close of play on Matchday 26 has gone on to lift the title 47 times. In the last 14 seasons alone, that team has been record 30-time champions Bayern on 11 occasions - including the last nine on the spin.
At this juncture last season, Leipzig were in the same position as Dortmund are now - four points adrift of Bayern. They ended the campaign some 13 points worse off than the champions. In 2018/19, Bayern overturned a six-point deficit at halfway to lead Dortmund on goal difference after 26 matchdays. They ultimately triumphed by a two-point margin.
In each instance, Bayern got the better of their nearest rivals during the run-in. They thrashed Dortmund 5-0 on Matchday 28 of 2018/19, and edged Leipzig 1-0 on Matchday 27 last term. As before, Der Klassiker with Dortmund, slated for Matchday 31, could have a major bearing on the destination of the 2021/22 title.
Between now and then, Bayern face Union (h), Freiburg (a), Augsburg (h) and Arminia Bielefeld (a), as well as Spain's Villarreal over two legs in the UEFA Champions League quarter-finals. Dortmund's focus is exclusively Bundesliga, with Leipzig (h), VfB Stuttgart (a) and Wolfsburg (h) to follow their upcoming trip to Cologne.
Post-Klassiker, Bayern's final push takes in games against Mainz (a), Stuttgart (h) and Wolfsburg (a). Dortmund finish with Bochum (h), Greuther Fürth (a) and Hertha Berlin (h).
If results were to mirror the reverse fixtures, Bayern - 3-2 winners in Dortmund in December - can expect 21 points down the back straight to BVB's 13. For Dortmund, that would translate into a 12-point shortfall on the final day.
It's a fanciful scenario, admittedly, and one that doesn't take into account the demands of Bayern's continental ambitions, or their personnel concerns.
If Bayern beat Villarreal in the Champions League, they will have to add a two-legged semi-final against Jürgen Klopp's Liverpool or Benfica to their agenda. The first leg is scheduled to take place between Bundesliga assignments against Dortmund and Mainz; the second just days before the southern derby with Stuttgart.
Influential midfielder Leon Goretzka should be back to help the cause immediately after the international break, but Alphonso Davies - one of the key pieces of the Julian Nagelsmann puzzle - is still some way off full-match fitness. Bayern dropped seven points across the Canadian left-back's first 16 Bundesliga appearances of the season. They've already given up eight in the nine he has missed in the first chunk of the calendar year.
Meanwhile, Dortmund have learned to win ugly - tradtionally a hallmark of champions - and without the services of Erling Haaland at that.
The 21-year-old hasn't started a game since scoring his 16th Bundesliga goal of the season in the Matchday 20 win at Hoffenheim, but did feature from the bench in recent 1-0 victories over Bielefeld and Mainz. Remember, this is the player with the best minutes-per-goal ratio in the Bundesliga (one every 75 minutes - 180 seconds ahead of Bayern's Robert Lewandowski in that regard).
US playmaker Gio Reyna - who set up Axel Witsel's 87th-minute winner in Mainz - has also made a timely recovery, and head coach Marco Rose still has first-choice defenders Manuel Akanji, Raphael Guerreiro and Mats Hummels to reintroduce to the fold.
With the business end of the season nigh, the stars are beginning to align for Dortmund in more ways than one.
Chris Mayer-Lodge