But Bayern suffered a blow after midfielder Javi Martinez sustained a shoulder injury and is almost certainly out of Wednesday’s game.
The Bundesliga giants had been struggling recently by their high standards and that led to the 72-year-old Heynckes replacing Carlo Ancelotti. And his return saw Bayern romp to a one-sided victory against relegation candidates Freiburg at the Allianz Arena thanks to goals from Thomas Muller, Kingsley Coman, Thiago, Joshua Kimmich and of course Robert Lewandowski.
Munich skipper Muller was thrilled with his side’s display. “We wanted to put on a great performance in front of our fans. There is no perfect game in football, but today it was close,” he said. “The change of manager is important, but as players we also have to improve.
“It was very good but we keep our feet on the ground and prepare for the game against Celtic.”
Heynckes said: “This is a positive start for us after a difficult few weeks. We have made a good game over long periods, but we have also allowed Freiburg three chances in the first half. That must not happen to us. We must be safer, more compact and cannot lose the ball when we are all going forward.
“Javier Martinez had to be taken off after an injury and that’s a concern. We don’t know yet how bad it is. He’s a tough boy and never usually asks to come off.”
The experienced manager received an absolute rapturous reception when he applauded the fans before kick off. But he almost got off to a terrible start with the visitors nearly netting with their first venture up the park in the fifth minute when on-loan Liverpool kid Ryan Kent was sent clean through on goal with alarming holes opening up in the home defence. Keeper Sven Ulreich – back-up to the injured Manuel Neuer – saved them with a fine stop with his foot.
And Freiburg were made to made to pay for that miss when Kent gave away possession in his own half with a heavy touch and Bayern worked the ball in for captain Muller to knock in from close range.
Freiburg’s Kent – who Brendan Rodgers had at Celtic and was linked with a summer loan move to Parkhead – had another chance when he forced a further save off Ulreich before Mike Frantz headed wide right in front of goal.
They looked shaky before the tension was eased with a second goal three minutes before the interval when Arjen Robben saw his low shot saved, but keeper Alexander Schwolow could only scoop the ball up for Coman who netted spectacularly with a looping, diving header.
The second half continued with Bayern having piles of possession and they were awarded a penalty on the hour mark after a harsh handball from a Robben cross. But referee Frank Willenborg was persuaded to check the video replay and changed his mind and awarded a corner instead.
Freiburg’s reprieve lasted all of three minutes when Thiago cracked in a terrific low strike from 25 yards.
And Lewandowski got his customary goal 15 minutes from time when strike partner Muller sent him through.
Kimmich got the final touch to a Robben cross in injury time to hand Celtic an ominous warning that Bayern are back.