The Ligue 1 giants have travelled to Parkhead having scored 19 goals in their last five games, making tonight a true baptism of fire for Ralston.
The 18-year-old will start the match at right-back, making him responsible for marking the most expensive footballer in the world, Brazil international Neymar.
However, despite Ralston having made just a handful of appearances for the senior side, Celtic fans appear quietly optimistic over his inclusion.
In fact, some supporters seem pleased to see Rodgers giving such a young player a chance on the biggest occasion:
ralston to boss it eazyyy
— Mark (@Mark_Williams97) September 12, 2017
— Badgie (@badgiebhoy) September 12, 2017
Ralston defo a risk worth taking a think.
— lee miller (@milsaa_) September 12, 2017
What a game for Ralston to play in. Great faith shown by Brendan. Mon the hoops
— Joseph (@josephduffy81) September 12, 2017
Ralston starts. Again, WTF do I know. Wonderful vote of confidence in the youngster from Brendan Rodgers. Hope he plays a blinder.
— Krys (@krys1888) September 12, 2017
Ralston v Neymar tonight.
— jamiep (@jpace88) September 12, 2017
Remember a young john Kennedy and David Marshall started against a world class Barcelona and did the job. Hope Ralston does the business.
— Conlon McFaulds (@conlonmcf) September 12, 2017
Ralston starting for the hoops the night, Academy player this time last season, now starting against PSG in the champions league ?
— Jacket (@Mabon_3) September 12, 2017
Playing Ralston shouldn't be seen as a big risk, he won't be viewing it like that. We've seen youth players shine on these nights before.
— A Grand Auld Team (@FritzAGrandAuld) September 12, 2017
Absolutely massive test for Ralston tonight! Delighted to see the youth getting into the first team! #COYBIG ???
— Jack Quinn (@JackQuinn323) September 12, 2017
Go on Ant Ralston, great night for the youngster.. ?
— Mark Lucas (@Mark_Lucas18) September 12, 2017
The team is in. As suspected Ralston plays. Huge baptism of fire for him. https://t.co/qgRosJrUV8
— GIGPOD (@GIGPOD) September 12, 2017
Tony Ralston will destroy Neymar, bench press him, throw him in the GB like a human sacrifice, then scream "ARE YOU NOT ENTERTAINED"
— Aylwin (@aylg1987) September 12, 2017
How are folk worried about Ralston when we literally played Ambrose against Messi?
— Rikos (@Rikos67_) September 12, 2017
Massive test for Ralston tonight. Also a massive vote of confidence.
— Kieran Caw (@Kieran_Celtic) September 12, 2017
Seeing a few rumours Ralston could be starting, tbh ad rather take a risk wae Ralston at rb than play Bitton at cb any day ?
— . (@Gunnie67) September 12, 2017
A big call from BR to start Tony Ralston but it makes sense allowing Lustig to move into CB beside Jozo. Looking forward to kick off!
— Daniel Bowers (@DanielBowers95) September 12, 2017
You've got this Ralston lad,make a name for yourself.
— Ben John? (@Thebenjohn) September 12, 2017
What do you make of Ralston being handed a starting spot for tonight’s game?
Should Rodgers be handing such a difficult task to such a young player?
Or could youth be the key to causing an upset against the bigger sides in this year’s competition?