Celtic crashed out of the Europa League after a horror start left them a goal and a man down inside the first minute of their second-leg tie against Sion.
Daniel Majstorovic was red-carded for a tackle inside the box, Pascal Feindouno scoring the resulting penalty.
The Guinean fired in a free-kick in the 63rd minute, before Charlie Mulgrew pulled one back for Celtic with 12 minutes remaining.
Giovanni Sio lobbed in the third for Sion to end Celtic's European season.
The result contrubited to a night to forget for Scottish football, with Rangers and Hearts also failing to reach the group stage of the Europa League.
It was a nightmare start for the visitors when, with less than a minute of the match played, Majstorovic was caught out of position during a speedy Sion counter attack.
Geoffrey Serey Die fed the ball to Guilherme Afonso, who was scythed down inside the box by Majstorovic as he raced in on goal.
Referee David Fernandez Borbalan had no hesitation in showing the defender the red card and Feindouno, who had been on trial at Celtic last year, dispatched the ball past Fraser Forster to put the home side ahead.
Down to 10 men, Mulgrew moved into the centre of defence with Joe Ledley taking up the left-back position and Georgios Samaras dropping deeper as the injured Afonso was replaced by Aleksander Prijovic.
CHANGE IN FORTUNES
Celtic won their first three games of the season - scoring eight and conceding only once.
Since, they have lost two of three and scored just one goal
Unsettled by their start to the match, Celtic struggled to get a foothold in the face of a buoyant Sion.
Mario Mutsch and substitute Aleksander Prijovic both had early chances, then Celtic survived wave after wave of attack instigated by Feinduono - one of five players listed by Sion that Fifa judged
ineligible to play
for the club due to a transfer embargo, with the Swiss outfit warned they could face sanctions from Uefa.
In the 27th minute Forster had to dive low to his left to beat out a Feindouno free-kick after Kayal was penalised for handball 25 yards out.
Minutes later Cha had to put in a crucial saving block on Feindouno after the striker had brilliantly made a yard of space for himself in the Celtic box.
After the restart it was midfielder Sio who took on the role of Celtic's tormentor; the Frenchman creating a barrage of chances and involved in the second goal; Ki Sung-yueng judged to have fouled him 30 yards from goal to hand Sion a dangerously positioned free kick.
Feindouno's initial effort was blocked, but he was allowed another by a static Celtic defence, with Forster helplessly watching the ball nestle in the corner of the net.
There was a glimmer of hope for Celtic in the 78th minute, when Mulgrew converted a free kick from 20 yards out to put Lennon's side once against within a single goal of securing their progression to the group stages.
But a mistake by Ki on the half-way line eight minutes from time gave Sion the killer blow they needed.
The Korean was dispossessed under little pressure from the mercurial Sio, who picked up the ball and ran all the way to the box before chipping Forster to slot home and end Celtic's run in Europe at the play-off stage for a second year running.
Full Time The referee signals the end of the game.
Didier Crettenand produces a right-footed shot from just outside the area that goes harmlessly over the bar.
Free kick awarded for a foul by James Forrest on Vilmos Vanczak. Free kick taken by Jose Adailton.
The ball is crossed by Du-Ri Cha.
The assistant referee flags for offside against Giovanni Sio. Fraser Forster takes the free kick.
Inswinging corner taken by Michael Dingsdag from the right by-line.
Substitution Kris Commons joins the action as a substitute, replacing Joe Ledley.
A cross is delivered by James Forrest, Andris Vanins makes a comfortable save.
Substitution Aleksandar Prijovic goes off and Lacerda Ramos Rodrigo comes on.
Booking Giovanni Sio goes into the referee's book.
81:48 Goal scored
Goal! - Giovanni Sio - FC Sion 3 - 1 Celtic A goal is scored by Giovanni Sio from just outside the box low into the middle of the goal. FC Sion 3 (3)-(1) 1 Celtic.
Sung-Yeung Ki takes the free kick.
Booking The referee books Gary Hooper for dissent.
Booking The referee shows Serey Die a yellow card for unsporting behaviour.
Free kick awarded for a foul by Serey Die on Gary Hooper.
Inswinging corner taken by Michael Dingsdag.
Shot by Giovanni Sio. Scott Brown gets a block in.
Serey Die challenges Georgios Samaras unfairly and gives away a free kick. Free kick taken by Georgios Samaras.
77:16 Goal scored
Goal! - Charlie Mulgrew - FC Sion 2 - 1 Celtic Charlie Mulgrew finds the net with a goal direct from the free kick from just outside the area high into the middle of the goal. FC Sion 2 (2)-(1) 1 Celtic.
Michael Dingsdag challenges Gary Hooper unfairly and gives away a free kick.
Gary Hooper is caught offside. Andris Vanins takes the direct free kick.
Joe Ledley takes a inswinging corner.
Substitution Beram Kayal leaves the field to be replaced by James Forrest.
Giovanni Sio takes a shot. Blocked by Beram Kayal.
Gary Hooper is ruled offside. Andris Vanins takes the free kick.
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