Celtic played two very young full-backs against the French club.
Celtic manager Brendan Rodgers has been speaking to the club's Twitter account following his side's 5-0 defeat to Paris Saint-Germain, and despite that humbling loss the Bhoys boss had nothing but praise for two of his young players.
It is fair to say things did not go according to plan, but the young Celtic pair will have learnt a lot from coming up against two of the most expensive footballers in the world.
"I (have) seen my two young full-backs playing against Mbappe and Neymar," Rodgers said. "I thought they did exceptionally well."
Both PSG players got on the score sheet but in honesty few clubs in the world could keep the club's expensively assembled forward line at bay.
Big things are expected of Ralston and Tierney, with the latter already making himself indispensable to Rodgers' side, and in years to come they may look back on Tuesday's defeat and accept that it turned them both into better players.
They will be hoping to do better for the rest of Celtic's European campaign but things are not going to get much easier with Bayern Munich and Anderlecht to come later this year.
BR: "I seen my two young full-backs playing against Mbappe and Neymar. I thought they did exceptionally well."— Celtic Football Club (@celticfc) September 14, 2017