The 67-year-old was pleased to return from a tough game with all three points, and praised the courage displayed by the home side.
A solitary first-half strike from Mario Gomez was enough to earn the Bundesliga leader all three points against a spirited home side, and Heynckes was thrilled to secure the win despite his side being far from its brilliant best.
"The game today was very difficult," he was quoted as saying by the club's official website. "The opponent is in trouble. They have played incredibly courageously, aggressively. That was a workmanlike victory - it was not brilliant, it was not glamorous, but in return you get three points."
It was a rare day of profligacy in front of goal for the runaway league leader, but Heynckes was happy to have secured all three points, insisting it is not always possible to win by a comfortable margin.
"We cannot win with three or five goals every time," he explained.
"We had to roll up our sleeves. It took us a while until the engine was warm. We have not had so many clear chances. In the second half, it was better, since we had the game under control. Overall, we had to work hard."