Bayern Munich eased past Celtic 3-0 in the Champions League on Wednesday to hand coach Jupp Heynckes a victorious return to the competition he won with them in 2013.
First-half goals from Thomas Mueller and Joshua Kimmich put them in the driving seat and Mats Hummels grabbed a third in the 51st minute to round off a dominant performance in which the 72-year-old Heynckes became the oldest coach in the competition's history.
Celtic were no match for the aggressive Bavarians, who were out to get their European campaign back on track after their 3-0 loss to Paris St Germain last month.
That result prompted the sacking of coach Carlo Ancelotti and the return of Heynckes, who led Bayern to the Champions League crown in a treble-winning 2013 season.
Bayern are now second outright in Group B on six points from three matches, three ahead of Celtic and three behind leaders PSG.
The hosts pressed high from the start and Celtic had a lucky escape after six minutes when Bayern's Thiago Alcantara put the ball in the net. The effort was ruled out, however, as Robert Lewandowski’s cutback was incorrectly ruled to have gone out of play.
Bayern, who also crushed Freiburg 5-0 in Heynckes' first league match on Saturday, completely overran the Celtic defence. "It was important after Saturday's 5-0 to also get back on track in the Champions League," Heynckes, in his fourth stint at the club, told reporters. "We want to advance and for that we needed to win and the team did it well over much of the game."
It was only a matter of time before Bayern scored, which they did in the 17th minute when Kimmich floated in a deep cross, Lewandowski's header was palmed wide but Mueller came in at the far post to drill home.
They did not let up and Kimmich got onto the scoresheet 12 minutes later with a clever, looping header from 14 metres.
Hummels, making his first Champions League appearance this season, added a third six minutes after the restart with a powerful header that gave Celtic keeper Craig Gordon no chance.
"We had more chances to score but we did not convert them. We were a bit sloppy towards the end," Heynckes said. "There are still things we need to improve, teamwork, the way we return from attack to defend, many small things."
The defeat for Brendan Rodgers's team means Celtic have now failed to win any of their 11 European matches on German soil.
"It was a hard game. In the first half we tried to press them," said Celtic captain Scott Brown. "They are a top quality side. We always try to press but you have to stay compact against top quality players."
"Hopefully, our fans can give them a fright at Celtic Park (in two weeks) and we can cause them some problems.