Pierre-Emerick Aubameyang, the Bundesliga's top-scorer, claimed his 23rd goal in as many league games as Borussia Dortmund laboured to a 1-0 home win over strugglers Ingolstadt on Friday.
Aubameyang's first-half winner was his 30th goal in all competitions for Dortmund this season.
Borussia remain third in the table, narrowing the gap behind RB Leipzig to three points, but 13 adrift of runaway leaders Bayern Munich.
Borussia, who have drawn Monaco in the quarter-finals of the Champions League, were missing a host of stars, but there was no disguising a poor display.
Ingolstadt, who enjoyed 14 shots on goal to Dortmund's 10, are second from bottom and seven points from safety, but matched Dortmund and should have been awarded a second-half penalty.
"I was already getting ready to save the penalty," admitted Dortmund's goalkeeper Roman Burki after the referee missed his foul on Dario Lezcano on 52 minutes.
"I was glad 'Auba' got his goal, because without it, things would have been even harder for us, but the most important thing was the three points."
Burki had a busy night and admitted Dortmund were tired from their rescheduled German Cup win at minnows Sportfreunde Lotte on Tuesday to reach the semi-finals.
With Germany winger Marco Reus injured and 19-year-old Ousmane Dembele suspended, Dortmund coach Thomas Tuchel rotated his squad.
US teenage international Christian Pulisic, 18, and Japan's Shinji Kagawa filled the attacking midfield roles behind Aubayemang.
The Gabon star needed just 14 minutes to add to his goals tally and remain two clear of Bayern Munich's Robert Lewandowski in the race to be the top scorer this season.
Kagawa started the move in midfield and fed Marcel Schmelzer, who provided the cross from the left which Aubameyang rifled home.
However, Dortmund lived dangerously in the second half and were far from convincing as Ingolstadt grew in confidence with Australia forward Mathew Leckie leading the attack.
Only Burki's close-range save denied Leckie.
With 30 minutes to go, Tuchel lost patience with the ineffective Raphael Guerreiro, who won just three of his 10 challenges, and replaced him with Germany's Julian Weigl in the defensive midfield.
Leckie could have again rescued a point just before the final whistle, but he skied a chance over the bar.