Derbies, rivalry matches and clasicos serve as useful mile markers over the course of a long soccer season. They give us an excuse to check in on two key teams, see how everything is going and see what has happened since the last time said teams met. With the Bundesliga's Der Klassiker -- Bayern Munich vs. Borussia Dortmund -- resuming Saturday in Dortmund (watch LIVE, 12:30 pm ET, ESPN+), let's indeed do some checking in.

What's happened since the last time these German heavyweights last faced off? To answer this question, I both dove into the statistics and spoke with former Bayern Munich and German national team captain Philipp Lahm.

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The teams are separated by just one point in the Bundesliga table

Since Bayern's 3-1 win over BVB in Germany's Super Cup on Aug. 17, Bayern's sixth straight win in the head-to-head series, both teams have battled injuries and random bouts of inconsistency. Borussia Dortmund have seriously missed star striker Erling Haaland, absent for six Bundesliga matches and three Champions League matches with injury. But other core players like left-back Raphael Guerreiro, winger Gio Reyna, midfielders Emre Can and Mahmoud Dahoud, attacking midfielder Thorgan Hazard and defender Mats Hummels have all missed time as well, while burgeoning star midfielder Jude Bellingham also suffered a minor injury last week; his status for Saturday is uncertain.

As the midway point of the season approaches, first-year manager Marco Rose has barely had a chance to field his full, first-choice lineup, even in practice. We therefore haven't yet gotten a clear vision of what Rose wants to implement in Dortmund, either. "He's had the rather poor luck of having a great many injuries to deal with," Lahm said. "For that reason he might have experimented around a bit, and it hasn't always worked well. I believe he's still in the process of finding the right system that fits for Dortmund, but for that, again, he needs healthy players."

BVB's issues mostly snuck up on them in Champions League play, where they began with two wins, but lost three straight matches by a combined 10-2 and were relegated to the Europa League knockout rounds. But even with a diminished lineup, they've managed to eke out key wins in league play, most recently winning 3-1 in Wolfsburg last Saturday.

Bayern's issues haven't been quite as significant, and they certainly haven't impacted the club's Champions League status: the 2020 European champions have won all five of their group stage matches so far by a combined 19-3. But 2-1 losses to Eintracht Frankfurt and Augsburg provided some unexpected dropped points, and they were eliminated from the DFB-Pokal in jarring fashion via a 5-0 loss to Borussia Monchengladbach.

New manager Julian Nagelsmann, who himself missed a couple of matches due to a positive coronavirus test, has been forced to juggle his lineups, particularly in the midfield.

Joshua Kimmich has missed time due to quarantine and a positive coronavirus test -- he's out for Saturday's match as well. Right-back Benjamin Pavard, who often tucks into a midfield role during buildup play, missed the first month of the season with an ankle injury, Corentin Tolisso missed the next month with a calf issue, and now summer acquisition Marcel Sabitzer has suffered a calf injury as well. Bayern still have Leon Goretzka, with Tolisso and Pavard both available, but they might not enjoy the same midfield advantage they typically do against BVB.

Despite Bayern's better form in Europe, the two teams are indeed separated by just one point in the Bundesliga table, and nobody else is within six points of the top. While the league has produced some pleasant surprises, it's easy to see this as a two-team race.

"Some teams have surprised me -- Freiburg being one of them," Lahm said. Freiburg are in fourth place and could have been higher if not for recent one-goal losses to Bochum and Bayern. "They've been doing an excellent job so far. But I believe that the championship will be decided between Bayern and Dortmund. I think Leipzig and Leverkusen have left some points behind, so I believe it will be a Bayern-Dortmund thing at the end."

A winner on Saturday would lead the way into Matchday 15.

BVB's poor injuries luck has been offset by good fortune in league play

Rose's side have overachieved their expected goal figures to date -- they're averaging 2.1 xG per match and allowing 1.6, but in terms of actual goals, they're scoring 2.5 and allowing 1.5. The over-achievement comes primarily from Haaland, who has managed to score 10 league goals on 7.1 xG in just 557 Bundesliga minutes -- the equivalent of 6.2 full matches. But the defense is perhaps lucky not to have suffered more mishaps: while they are ninth in the league in goals allowed and sixth in shots allowed per possession (0.12), they are 11th in xG allowed and 16th in xG allowed per shot (0.14).

Rose's style is one of ball control, but the juggled midfield has left them as vulnerable as ever to counterattacks.

As one would expect, BVB have been a profoundly different team with and without Haaland. "Erling Haaland is an extremely important player for Borussia Dortmund," Lahm said, "not just in terms of his football skill, but also in terms of his attitude, what he does for the team, what he does for the other players, pulling them along, infecting them with his enthusiasm and really helping them all to get better."

When Haaland is in the lineup, they are prolific and free-flowing -- in his seven league matches, they have averaged 2.6 points per game and 3.3 goals with 1.9 goals allowed. Without him, they're more conservative, averaging 1.7 goals, but allowing just 1.0 and still squeezing out 2.0 points per game.

The Norwegian striker's presence is obviously impactful, but Donyell Malen's recent play has to be encouraging, too. The 22-year old, who arrived from PSV Eindhoven in July, has scored only twice in league action, but those goals came in his last two matches. His shot volume has slowly increased as well.

"He's joined a new club, it's a new league, so things take their time," said Lahm. "He's certainly a player of excellent skills, and a player you simply need to let play and you need to give some time to. Things take time."

Malen's 23-yard firecracker in the 55th minute against Wolfsburg gave BVB a lead they wouldn't relinquish, and it'll be interesting to see how he fits into Rose's plan with Haaland back to full strength.

Despite the shuffled midfield, meanwhile, Bayern remains Bayern

They are statistically dominant, even in losses. Bayern average 3.0 xG per match (0.9 more than second-place RB Leipzig) and 3.2 goals (0.7 more than BVB). They attempt far more shots per possession than anyone else, and average the highest xG/shot in the league. In all competitions this season, star striker Robert Lewandowski already has 25 goals in 20 matches, winger Serge Gnabry has eight goals, do-it-all Thomas Muller has six goals and 12 assists, and a resurgent Leroy Sane, moving back to his natural left wing -- he played on the right for previous manager, Hansi Flick -- already has nine goals and nine assists.

"I believe Julian Nagelsmann simply saw where Leroy Sane can play with the utmost self-confidence and placed him back there," said Lahm of Sane's improvement. "Also, a player who changes clubs like Leroy a year ago, it's important to gain that self-confidence by simply being allowed to play several matches in a row. There can be good matches and bad matches amongst them, but that kind of approach can reinstate the confidence in a player."

Sane has played 1,442 minutes in all competitions this year, nearly 60% of what he logged all of last season (2,454).

Bayern are almost as dominant defensively, allowing both the fewest shots per possession and lowest xG per shot. They also have the most set-piece goals and have allowed the fewest; thanks in part to the addition of Dayot Upamecano from Nagelsmann's former club, RBL, they can challenge opposing attackers with almost shocking success. Left-back Alphonso Davies has won 80 of his 123 duels this season (65%), while Upamecano and fellow centre-back Lukas Hernandez have combined to win 80 of 120 (67%). Their DFB-Pokal loss to Gladbach, in which they allowed a steady stream of high-quality scoring chances, was the exception to basically every rule.

In Nagelsmann, Bayern have found a natural successor to both Pep Guardiola (who managed the club from 2013-16) and Flick (2019-21).

"I believe that Julian is quite a fan of Guardiola's and has taken his model," Lahm said. "Bayern under Guardiola became this kind of varied approach: sometimes three [at the back], sometimes four, sometimes four in a defensive mode, sometimes three in an offensive mode. Nagelsmann is a young, very modern type of coach, and with Guardiola kind of having left his mark on the Bundesliga I think he's become quite a model to follow."

As one would expect, they've been less impressive without Kimmich, the No. 2 midfielder in the ESPN 100. They indeed lost to Augsburg on Nov.19, and they achieved bare-minimum advantages in wins over Dynamo Kyiv in the Champions League (2-1) and Arminia Bielefeld (1-0).

"Obviously Kimmich is an extremely important player for Bayern Munich," said Lahm. "That is true today, and certainly also in the future with Goretzka. If such key players, such as Kimmich, are missing during a top match, that's something not to be taken lightly. That certainly does not help."

This has only been so much of a rivalry of late

While Bayern won only six of 10 in the series between Nov. 2016 and Aug. 2019, they've since won six in a row by a combined 18-7. BVB is good at taking the fight to the German champs, taking leads of 2-0 (in Munich) and 1-0 (in Dortmund) in last season's league clashes, but Bayern reeled them in each time. Over these six matches, Bayern has averaged 16.3 shots and 2.5 xG per match to BVB's 8.2 and 1.2. They've enjoyed higher xG in five of six matches, more touches in four and a higher pass completion rate in five.

BVB has an opportunity with Haaland's return and a Kimmich-free Bayern midfield, but it's hard to bet against a winning streak. "Haaland is back after his injury, so that is definitely an important factor," Lahm said, "and also they'll be playing in Dortmund in their own stadiums, so I expect this to be a very close match.

"But I personally have my bets on Bayern Munich."

That's usually a pretty good bet.