Resurgent Dortmund seek consistency in top-four fight
Dortmund sit one point ahead of fifth-placed RB Leipzig, having been six points behind the Saxons at Christmas.
Dortmund are a club heavily dependent on the income the Champions League brings, and have only missed the top four once in the past 13 years.
On Sunday, they face the same opposition against whom their season started to unravel last October.
After a chaotic and pulsating 3-3 draw in Frankfurt, Dortmund lost four of their next nine as clouds gathered around the future of coach Edin Terzic.
Five months later and Dortmund look to have steadied the ship, having lost just one of their past 14 and reaching the Champions League last eight.
But their strong results have come despite wildly inconsistent form -- sometimes during the same match.
Nowhere was this clearer than in Wednesday's 2-0 Champions League win over PSV Eindhoven, where Dortmund swung from having complete control to hanging on for dear life.
Terzic was at a loss to explain his side's inconsistency, telling DAZN "we played the best 30 minutes we played this season. Then in the second half, we completely stopped playing.
"We're happy about the first half and frustrated about the second. We need to turn this phase from the first 30 minutes into a 90-minute performance."
One positive is the return to form of Jadon Sancho, who has scored in his past two games and is beginning to resemble the player who made a big-money move to Manchester United in 2021.
Sancho failed to deliver at United and spent the majority of this season banished from the first team after falling out with coach Erik ten Hag.
Dortmund sporting director Sebastian Kehl could not resist a dig at Sancho's parent club after the win on Wednesday, saying "having Jadon in the squad enriches every team.
"It is clear that he would need time. Now he's rewarded himself with important goals."
Sixth-placed Frankfurt have a strong record against the top sides, beating Bayern and Leipzig so far this season.
Dortmund's top-four rivals Leipzig take on 16th-placed Cologne on Friday, giving them the chance to lay down the gauntlet to Terzic's men.
At the top of the table, Bayern can keep their slim title hopes alive with a win on Saturday's trip to last-placed Darmstadt.
Leverkusen, still unbeaten and 10 points clear with nine games to play, face a tricky tie away at Freiburg on Sunday.
One to watch: Deniz Undav (Stuttgart)
Serhou Guirassy may have grabbed the headlines for Stuttgart this season, but 14 goals and five assists in 21 league matches have now earned team-mate Deniz Undav a first international call-up.
Germany coach Julian Nagelsmann said Thursday "Deniz has a great ability to read spaces. He runs a lot, is hard working and has a good nose for goal", with the 27-year-old now in contention to feature for the hosts at Euro 2024.
Stuttgart were relegation candidates last campaign, Undav's arrival on a season-long loan from Brighton in the summer has helped the club up to third this term.
Key stats
67 - Bayer Leverkusen have 67 points with nine games remaining. Last year, Bayern and Dortmund finished on 71 after 34 games, with the Bavarians winning the title on goal difference.
0 - Leverkusen are unbeaten. No team has ever gone unbeaten through a Bundesliga season.
1 - Union have lost one -- and won four -- of six home games since Nenad Bjelica was named coach. They host Werder Bremen on Saturday.
Fixtures (1430 GMT unless stated)
Friday
Cologne v RB Leipzig (1930)
Saturday
Wolfsburg v Augsburg, Union Berlin v Werder Bremen, Heidenheim v Borussia Moenchengladbach, Darmstadt v Bayern Munich, Mainz v Bochum, Hoffenheim v Stuttgart (1730)
Sunday
Freiburg v Bayer Leverkusen, Borussia Dortmund v Eintracht Frankfurt (1630)