‘Auba’ – the 2015 African Player of the Year – headed second-placed Dortmund into a 77th-minute lead at home, but replays showed he was offside when Lukasz Piszczek launched his cross.
It was harsh for visitors Ingolstadt who looked to have taken the lead midway through the second-half when Dortmund captain Mats Hummels scored an own goal.
Hummels’ backpass flew over goalkeeper Roman Buerki on 66 minutes, but the referee did not give the goal after spotting an Ingolstadt foul in the build-up.
Aubameyang put the game beyond doubt by drilling home Henrikh Mkhitaryan’s pass on 86 minutes for his 20th goal in 19 league matches.
“I didn’t score last week (against Moenchengladbach), so it was important to stay focused,” said Aubameyang, who was unaware he was offside for his first goal.
“In the moment, I didn’t see I was offside, I just headed the ball in.
“We have conceded a few goals this season which were offside, so things balance themselves out.”
Aubameyang has already reached his goal for the season having bet Dortmund coach Thomas Tuchel he would score 20 goals before the campaign started, reports AFP.
“It’s true I’ve achieved my goal, but I haven’t yet managed to fulfil my bet with the coach, you’ll have to be patient,” he told reporters when asked for details of his bet with Tuchel.
Gabon international Aubameyang is the top scorer in Germany’s top flight, three ahead of Bayern’s Poland striker Robert Lewandowski.
The result puts Dortmund five points behind Bayern, who host Hoffenheim on Sunday, and stretches their lead over third-placed Hertha Berlin to 10 points.
Hertha threw away a 2-0 lead as hosts Werder Bremen roared back with three goals in ten second-half minutes to claim a point in a 3-3 draw.
Cote d’Ivoire veteran Salomon Kalou struck Berlin’s third goal to leave Hertha 3-1 up in Bremen with 20 minutes left.
Then Bremen veteran Claudio Pizarro netted a penalty before defender Santiago Garcia fired in a shot which was later credited to Pizarro, who nudged the ball over the line to level the scores.
Bayer Leverkusen climbed to fourth with a 3-0 win at Hanover 96, who dropped to the bottom, with Javier Hernandez scoring twice in the romp.
‘Chicharito’ converted a penalty, then drilled home his 13th league goal in 16 matches.
He has now scored 21 times in all competitions this season since joining from Manchester United.
Schalke have youth to thank for their 2-0 win at Darmstadt as dynamic midfielders Max Meyer and Leroy Sane, who are both 20, scored either side of halftime.
The win leaves the Royal Blues fifth in the table and relieves some of the pressure on coach Andre Breitenreiter after last Sunday’s shock home defeat against Bremen.
Schalke and Leverkusen’s wins mean Borussia Moenchengladbach drop from fourth to sixth after Friday’s 1-0 defeat to mid-table Mainz.
Mid-table sides Augsburg and Eintracht Frankfurt fought out a goalless draw in Bavaria.
Strugglers Stuttgart are two points clear of the relegation places after their 2-1 win at home to mid-table Hamburg.
Stuttgart’s new signing Artem Kravets, who arrived earlier this month from Dynamo Kiev, headed the winnner on 88 minutes for his first Bundesliga goal.
On Sunday, Champions League side Wolfsburg host Cologne looking to bounce back from last Sunday’s shock defeat in Frankfurt as they prepare to face Gent in the last 16 in Europe next month.
