"You have to take into account that we had another tough game on Tuesday, but we still played intelligent and clever football," said Heynckes on Bayern's official website.
"We were highly motivated and took control right from the start. Once we'd taken the lead, I knew our forwards were always good for another goal.
"The most important thing is keeping it tight at the back. We dominated the match and prevented Hoffenheim creating any chances."
Bayern remain at the top of the Bundesliga table with seven wins out of seven matches.