Beating the Scottish champions may not have been a surprise, but doing so in the manner in which Bayern achieved it – playing with energy, purpose and real aggression – will have left the club and the fans feeling highly optimistic for the rest of the veteran’s fourth stint in charge.
Thomas Müller, Arjen Robben and Jerome Boateng all started against the Hoops, which spoke volumes as to why club chairman Karl-Heinz Rummenigge was so keen to bring Heynckes back in at the start of the month.
Of that trio, only Müller started the defeat against Paris St-Germain on Matchday 2 that ultimately cost Carlo Ancelotti his job (though Boateng was absent with injury). Breaking from his predecessor, Heynckes restored Robben to the XI, while Müller and Boateng rewarded him with outstanding displays.
Speaking after the game, Heynckes revealed his slight dissatisfaction that Celtic were able to test goalkeeper Sven Ulreich on a number of occasions in the second half, but overall he was delighted with a win that reaffirmed the Reds’ resurgence since his return.
"Thomas (Müller) played an incredible game today. We analysed the opponent and prepared how we could get players like him, Robben and Kingsley Coman to perform at their best and they did that,” said the Mönchengladbach native, who became the oldest man to coach a side in the Champions League at 72 years and 162 days.
Watch: Bayern's record-breaking 2012/13 season under Jupp Heynckes
“When someone wants to be successful, then things have to adjust and improve to help that and it takes time. It’s fun for me because the team is highly motivated and the whole training team is perfectly set, and that set up can only help the team."
There is no doubt that the feel-good factor has returned to the club since Heynckes walked back through the door at Säbenerstraße. “Jupp Heynckes makes everyone in the team feel important, even those who didn't play. That's what he does,” said Boateng. The Germany defender’s post-match tweet also told its own story:
The contrast with the performance against PSG in the last round was remarkable. Both with and without the ball, the Reds looked like the Bayern of old, harrying the opposition into errors and attacking intelligently, with their emphasis on width particularly noticeable.
Joshua Kimmich was a marauding presence down the right and scored a second goal of the Champions League campaign with a stunning header. A similar threat was provided on the opposite flank by David Alaba and the impressive Coman.
The result and performance should re-ignite hopes that Bayern can go deep in the competition this season and compete with the continent’s best once again, but it also sets them up perfectly for an extremely testing run of games. They travel to Hamburg and Leipzig in the league, host Leipzig in the DFB Cup, then face Celtic in Glasgow and finally contest Der Klassiker with Dortmund at the Signal Iduna Park.
“We had made the first few steps, now we have two away games against Hamburg and Leipzig,” said Heynckes. “At the moment I see how very motivated the team is and it's very positive.” There is still much work to be done, but make no mistake: Bayern have their swagger back.