Ahead of Der Klassiker on Saturday, Bundesliga leaders FC Bayern München's lead on second-placed Borussia Dortmund has been - their smallest lead since Matchday 16.

Why might that gap expand or contract this weekend? Allow bundesliga.com to explain the tactical nuances that could come into play...

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Aubameyang's pace and Bayern's makeshift defence

Pierre-Emerick Aubameyang has proven a dangerous proposition for many a defence this season, scoring 22 goals in the Bundesliga. Add in his four assists and the African Player of the Year has been responsible for a BVB goal within every 77 minutes he has played. Although his finishing has improved enormously since shifting from the wing to centre forward, the Gabon striker has been clocked covering 30 metres faster than Usain Bolt, and his turn of pace remains his most dangerous asset.

Bayern may have only conceded a league-low 13 goals this season, but with Jerome Boateng, Javi Martinez and Holger Badstuber injured, Pep Guardiola has had to field midfielders David Alaba and Joshua Kimmich at the heart of his defence in recent weeks. Kimmich's Bundesliga career is only eight starts old, and whilst Alaba might be quicker than any of the aforementioned centre backs, he is not quick enough to recover should Aubemeyang catch one or both of them out of position on the counter-attack. "We can't stop Aubameyang one-on-one," said Bayern coach Pep Guardiola. "We'll have to play as a team."

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Bayern's wingers and Dortmund's reluctant full-backs

Whilst injuries have denied Bayern Arjen Robben and Franck Ribery in tandem for much of this season, Douglas Costa and Kingsley Coman have deputised with aplomb. One of the reasons 'CoCo' has proven every bit as dangerous as 'Robbery' is that each player is expected to interpret the position in the same way - when Bayern are in possession, if the winger is on the opposite flank to the ball he must stay there rather than drift inside to get involved in the build-up play. Guardiola once substituted Thierry Henry for failing to respect that point when at Barcelona, despite the Frenchman scoring as a result. The tactic may leave Costa or Coman bored for a few minutes, but it means their teammates always have the option of switching play if the midfield gets too busy.

This could prove particularly telling against Dortmund. Thomas Tuchel has seemed unsure on which player to start at left-back in recent weeks, with Marcel Schmelzer and Erik Durm alternating. Both prefer to overlap than to defend - the latter grabbed his first goal of the season in Wednesday's 2-0 win at SV Darmstadt 98 - and this could leave space for the Bayern wingmen, whomever of them plays.

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Salt and pepper

Guardiola and Tuchel are known to enjoy a positive working relationship off the field, and BVB's play has increasingly come to mimic Bayern's. Tuchel's Dortmund keep possession far more than did Jürgen Klopp's, and if high defensive lines, inverted wingers and an attack willing to drop deep to facilitate a possession-based approach have seen BVB pick up two more points than Bayern since the reverse fixture, then it also makes them easier for Bayern to predict.

Both sides are likely to line up with four at the back with attacking full-backs, a midfield three anchored by an orchestrator rather than a ball-winner, and a fluid attacking triumvirate behind Aubameyang and Robert Lewandowski respectively. Without many overloads - where the attacking team might expect to create two-on-one or three-on-one circumstances against the opposition defence - it is possible the sides could cancel each other out.

Read: the Bundesliga's salt and pepper

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Guardiola's subtle tactical changes

Whichever coach spots a potential tactical advantage more quickly is likely to prevail. Dortmund's main distributor from the base of midfield has been Julian Weigl of late - the 20-year-old was accurate with 115 of his 126 attempted passes against Darmstadt. Those are Xabi Alonso-esque numbers, but the reverse fixture shows how wily Guardiola can be.

With the scores at 0-0 and Martinez being denied space by BVB's pacy attack, Guardiola switched Martinez and Boateng around. The Spaniard had whispered the instruction to his captain Philipp Lahm, and the result, though seemingly minor, was resounding. With Martinez now marking Henrik Mkhitaryan, Boateng had space to distribute into the space behind Dortmund's defence. His delivery was better than a Martinez on the comeback from injury, and Boateng ended Bayern's 5-1 win at the Allianz Arena with two assists from centre-back.

Guardiola is not taking anything for granted, though. "The title won't be done and dusted if we win," said the Spaniard. "There's still a long way to go."

Stuart Telford