Left-back Kieran Tierney completed 90 minutes during the defeat to Bayern Munich – and Celtic fans ripped into him on Twitter for his performance.
The 20-year-old is regarded as one of the best talents at Parkhead, but he was part of a Bhoys defence that struggled to handle the German heavyweights.
Brendan Rodgers’ side suffered a 3-0 away defeat in the Champions League group stages and it means they are likely to be competing for third in the group to reach the Europa League.
Thomas Muller and Joshua Kimmich scored first-half goals for hosts Bayern to put them firmly in the driving seat, while defender Mats Hummels added a third in the second period.
The Scottish giants host Bayern in their next European outing and will be hoping to put up a better fight with home advantage.
Celtic fans on social media were critical of youngster Tierney for his display and believe he dipped well below his usual standard.
This Is Futbol has rounded up some of the best tweets:
https://twitter.com/CelticBhoy1888/status/920742675363614720
Even Tierney seems lost in defence. #Celtic
— Mo (@Notts52) October 18, 2017
https://twitter.com/Johnny_Scotland/status/920727321547608065
https://twitter.com/johnhowley_/status/920741769440038912
I love Tierney but he gets let off far too easy sometimes because he's a celtic fan
— Paul Doyle (@pauldoyle98) October 18, 2017
https://twitter.com/metalrafferty/status/920749703041515523
Tierney really needs to work on his passing!
— James McKenzie (@JamesWHMcKenzie) October 18, 2017
I don't know what Tierney has been told to do tonight but it isn't working. Looks like he doesn't know if he's playing left-back or c-half.
— Drummy Dziekanowski (@PolskaBhoy) October 18, 2017
Tierney is one of the most consistent performers in the Celtic side, but even the defender couldn’t cope with the pace of Bayern.
The full-back struggled defensively to handle the likes of Muller and Arjen Robben, but the youngster will surely learn a great deal from facing some of Europe’s elite attackers.
He did threaten to score Celtic’s only goal of the game with a long-range effort and attempted to make inroads in the final third, but found it difficult with little possession.