By ESPNSTAR.com staff
A brace from both Arjen Robben and Claudio Pizarro helped Bayern book a spot in the last 16 of the cup competition and Heynckes believes that their sheer grit was key in the victory.
He said on Bayern's official website: "You could see my players were utterly determined to make the last sixteen.
"Kaiserslautern put up enormous resistance in the first half.
"I made a lot of changes, but my team still played as a unit, with plenty of ideas and great discipline.
"I think the players deserved that today. All credit to the lads."
Robben, who was captain for the day, admitted that the scoreline flattered them and the match was tougher than it looked.
"Four-nil sounds easy, but it was tough, so I'm proud of the lads. We worked very hard," he added.