James Forrest was sent off as Celtic let a first-half lead slip on the way to a bruising defeat in Salzburg.
It was a dream start for the Scottish Champions in Austria in this Europa League tie when Odsonne Edouard fired them ahead after two minutes.
But Munas Dabbur and Takumi Minamino scored after the break, before Forrest was red-carded after conceding a penalty, which Dabbur converted.
Zlatko Junuzovic also hit a post as Celtic had no response.
After an assured defensive performance in their opening 45 minutes, the Austrians picked holes in Celtic with poor defending at all three goals.
Their opening win over Rosenborg leaves them level on points with Salzburg and Germans Leipzig, who beat the Norwegians 3-0 in the other group fixture.
A case for the defence
Celtic’s defence has so often been maligned, and in the shadow of the Austrian Alps it was at times their biggest asset and at others their worst enemy.
Brendan Rodgers set his side up with a familiar three at the back, knowing Kieran Tierney and Forrest could make it a flat five.
But few could have predicted the start.
Against a side who have not lost at home in almost two years, Celtic were ahead in just over a minute as Edouard outmuscled Andre Romalho, swivelled and guided the ball low past Alexander Walke on the angle.
Celtic’s record signing found the net again just before the break only to see the assistant referee’s raised flag deny him number two, but in the 44 minutes in between, it was all about the defence.
The half ended with the home side pouring forward and the second period started exactly the same with Craig Gordon forced into an early save from Dabbur. The Celtic backdoor continued to bend and creak but still it stood.
Dabbur did break through when Hannes Wolf cut back inside the box and the Israeli swept home low past Gordon. All of a sudden Celtic looked tired, vulnerable and a little unorganised.
When Minamino slotted past Gordon with the Celtic defenders falling over themselves, it looked to be unravelling spectacularly.
And as the wheels came off, they went flying.
Forrest had no real complaints at his red card after bringing down Andreas Ulmer inside the box and Dabbur looked the coolest customer in Austria as he stepped up to slot home number three from the spot.
Celtic swagger has gone – analysis
Celtic went into this match making all the right noises, but behind the scenes there was concern.
Salzburg were in red-hot form at home and they knew their visitors’ stuttering start to their own domestic season could be seized upon and exploited.
And when the home side turned the screw, Celtic had no answers. That will be of huge concern to Rodgers, who has continually talked about progression in his first two years in Glasgow.
Crashing out of Champions League qualifying in Athens was the first sign that progression was stalling. In Salzburg there was a realisation that they have a long way to go to get anywhere near where the former Liverpool manager wants them to be.
The swagger that led this group of players to a double treble looked gone. The zip, drive and belief was missing and defensive deficiencies were, at times, badly exposed by a very decent side.
Two years ago this group would have relished a tough test – more often than not, they rose to the challenge. But the pre-match concern was justified and Celtic need to find their mojo if they’re to compete with the best.
Source BBC News