Borussia Dortmund were well short of their best against Ingolstadt, but got the points courtesy of Pierre-Emerick Aubameyang.
Pierre-Emerick Aubameyang scored a first-half winner as Borussia Dortmund edged to a 1-0 triumph over struggling Ingolstadt, boosting their Champions League qualification hopes.
The Gabon international continued his electric form with an early strike that moved him on to 23 Bundesliga goals this season and nine from his last five across all competitions.
Dortmund, who lost to Hertha Berlin in their last league match, were unconvincing in victory, but nonetheless strengthened their position before the sides around them play their own top-flight matches this weekend.
Thomas Tuchel's men moved to within three points of RB Leipzig in second and stretched their lead over top-four rivals Hoffenheim and Hertha to four and six respectively.
Ingolstadt stay second from bottom and have now won just one of their last seven in the league despite a brave performance that saw them denied what looked like a strong penalty claim for forward Dario Lezcano in the second half.
Aubameyang passed a late fitness test to return to the Dortmund team as one of three changes and he was the man to open the scoring after just 14 minutes.
Shinji Kagawa's throughball released Marcel Schmelzer down the left and Aubameyang swept home the captain's precise cross with a left-footed finish past Martin Hansen.
Ingolstadt came close to responding when home goalkeeper Roman Burki had to display impressive reflexes to keep out Mathew Leckie's close-range header.
Alfredo Morales could only steer wide a headed chance of his own and Burki had to get out quickly to deny Sonny Kittel as the visitors continued to carry a threat.
At the other end, Kagawa's cross led to Christian Pulisic having a shot blocked and Erik Durm slamming over from the rebound, before Raphael Guerreiro fired wide from a good opening just before the break.
Straight after the restart, Leckie fired well off target from a glorious chance when a mix-up between Matthias Ginter and Sokratis gave him the opportunity.
Ingolstadt then had a credible shout for a spot-kick turned down after Burki appeared to bring down Lezcano in the area when the forward latched on to Kittel's flick-on and turned away from Lukasz Piszczek.
Sokratis prodded an effort just wide from Guerreiro's corner for Dortmund and Durm's long-range strike tested Hansen, but the match remained in the balance going into the closing stages.
Tuchel, who introduced Andre Schurrle from the bench in a bid to wrap up the result, was angered when Gonzalo Castro's free-kick appeared to strike the arm of a defender in the wall.
But that did not prove to be a decisive moment as Dortmund did just enough in their last game before the international break, maintaining their unbeaten home record in this season's Bundesliga.