The Scottish champions were embarrassed on their home turf by Sparta Prague, a team they were expected to defeated and ultimately needed to defeat in order to have any chance of qualifying for the knockout stages of the competition.
A hat-trick from Lukas Julis had the game won before Ladislav Krejci added a fourth in injury time. Leigh Griffiths netted for Celtic after coming off the bench and briefly threatened to ignite a comeback, but the home side were second best for most of the night.
They now need to win all three of their remaining games to have any chance of qualifying, though manager Neil Lennon even admits “Europe is gone”.
Player ratings scale - 10: One of best performances you've seen. 9: Outstanding. 8: Very good. 7: Good. 6: Average. 5: Poor, 4: Very poor. 3: Terrible day at office. 2: Abysmal. 1: One of worst performances you've seen.
. GLASGOW, SCOTLAND - NOVEMBER 05 : Celtic's Shane Duffy (left) is dejected as his side concede a 4th during the UEFA Europa League match between Celtic and Sparta Prague at Celtic Park, on November 05, 2020, in Glasgow, Scotland (Photo by Craig Williamson / SNS Group)
Shane Duffy and Nir Bitton react to Celtic looking a fourth goal against Sparta Prague. Picture: SNS Photo: Craig Williamson - SNS Group
. GK - Scott Bain - 6
Made one great first half save and wasn't at fault for any of the goals. Did almost cost his side with a very poor pass early in the second half, though. Photo: Alan Harvey - SNS Group
. DR - Jeremie Frimpong - 5
Had a couple of great runs, as expected, but defensively he was found wanting and his final ball was inconsistent. Photo: Craig Foy - SNS Group
. LB - Diego Laxalt - 5
The Milan loanee has been impressive since coming in, but not tonight. Didn't do enough going forward to affect the game. Photo: Craig Foy - SNS Group
. CB - Nir Bitton - 5
A fine Scottish football centre-back, there is no doubt, but questions remain of his ability to defend at the European level. Photo: Ross MacDonald - SNS Group
1. GK - Scott Bain - 6
Made one great first half save and wasn't at fault for any of the goals. Did almost cost his side with a very poor pass early in the second half, though. Photo: Alan Harvey - SNS Group
2. DR - Jeremie Frimpong - 5
Had a couple of great runs, as expected, but defensively he was found wanting and his final ball was inconsistent. Photo: Craig Foy - SNS Group
3. LB - Diego Laxalt - 5
The Milan loanee has been impressive since coming in, but not tonight. Didn't do enough going forward to affect the game. Photo: Craig Foy - SNS Group
4. CB - Nir Bitton - 5
A fine Scottish football centre-back, there is no doubt, but questions remain of his ability to defend at the European level. Photo: Ross MacDonald - SNS Group