Celtic blew a 4-0 aggregate lead to sensationally lose 5-4 on aggregate to LASK of Austria and miss out on a valuable place in the Champions League.
Captain Callum McGregor put them into an early lead on the night and seemingly on course after last week’s 3-0 win in Glasgow.
But Martin O’Neill’s side were pushed back and against the ropes for the whole of the second half as LASK rained in 39 shots on goal.
They found a fourth goal in the 90th minute to force extra-time, and then Samuel Adeniran smashed in to secure a place in the league phase which could be worth as much as £40m.
There was even time for a penalty for the hosts but Adeniran was denied.
Celtic missed out at this stage last season by losing to Kairat of Kazakhstan but this defeat will hurt even more given their superiority in the tie.
Now a place in the Europa League beckons for Celtic and regrets about what could have been.
The victors will, however, join the league phase draw on August 27. Matchday one of the Champions League is on September 8.
Kasper Hogh twice went close in the opening 15 minutes as Celtic threatened on the break but the striker just failed to connect with a low cross and then curled too close to goalkeeper Lukas Jungwirth.
The home side rattled the post with a deflected shot from range before McGregor struck home the opener.
Yang Hyun-Jun did all the approach work down the left and cut the ball back for his captain who smashed in a low shot from the edge of the box.
That left the home side 4-0 down on aggregate but heads didn’t drop and Moses Usor gave them some hope with a fine finish to a flowing move before the break.
That gave fans and players alike belief and that only grew at the start of the second half when Robert Ljubicic crunched home from 20 yards.
That made the aggregate score 4-2 to Celtic and nerves were really kicking in. And the unthinkable was looking probable when Adeniran bent in a wonderful third for the hosts from long range.
That was 4-3 on aggregate with a full half hour left – and Adeniran then rattled the underside of the crossbar with a volley as Celtic were in full retreat.
Celtic were pinned back and a fourth LASK goal looked almost inevitable – and did come as the clock ticked past 90 minutes.
Viljami Sinisalo made a wonderful save but Florian Flecker was on hand to head into the back of the net and force extra time.
The first period was uneventful but Adeniran then thumped in his second of the night from 25 yards to find the bottom corner and put LASK ahead on aggregate with 11 minutes of the tie left.
The dangerous American then saw a penalty well saved by Sinisalo but it did not matter as LASK won through.
An Azerbaijani club formed just nine years ago will debut in the Champions League alongside them.
Sabah were just seconds from elimination against Israeli champions Hapoel Beer-Sheva when substitute Tellur Mutallimov scored in the last minute of stoppage time to force extra time.
Sabah’s Gabon striker Orphe Mbina then scored with a header in the 101st minute and Joy-Lance Mickels added one in the 115th to make it 5-2 in the second leg and 6-4 on aggregate.
