Former striker John Hartson says Celtic go into Tuesday's Champions League clash away at Barcelona with nothing to lose.
Hartson, who scored for the Hoops when the two sides drew 1-1 at the Nou Camp in 2004, says Neil Lennon's current crop of players shouldn't be overawed by the occasion.
"They'll be looking forward to tomorrow night at Barcelona," he told Sky Sports News. "There's no pressure on the Celtic players - no-one realistically expects them to get anything from the game.
"Not many teams do take anything from Barcelona at the Nou Camp so it will be a tough ask but they can go and enjoy it and hopefully play with a little bit of freedom."
La Liga leaders Barcelona go into Tuesday's match on the back of an incredible 5-4 victory over Deportivo which featured a Lionel Messi hat-trick - his 10th for the club.
Hartson says the Celtic players should relish the chance to compete with one of the best players the game has ever seen but cannot afford to let him - or his talented team-mates - dictate terms.
"I don't know if there is a player out there in world football who could go man-for-man with Lionel Messi but it's extremely difficult to mark the greatest player in the world right now and arguably the greatest there's ever been," he said.
"And it's not just Messi; they've got Xavi, Iniesta, Alves. They've got top, top players all over the park, really.
Celtic scored five goals of their own in their last outing - a rout of St Mirren - and Hartson says they should travel to the Nou Camp in confident mood following their last-gasp 3-2 victory over Spartak Moscow earlier in the month.
"It was a massive result because it was the first points that they had taken in the Champions League since eight or nine years ago," reflected Hartson.
"Yes, they've had good results in the qualifiers but in terms of the group stages that was a huge win for them and they deserved it.
"I thought they started the game well - Gary Hooper was outstanding on the night and if you play with one up front, your frontman is very, very important to you.
"So that was a big monkey off their back if you like - they've currently got four points from the first two games, so they can afford to lose a game.
"The most important thing for me is that if they don't get through in terms of the top two, they finish third so they go into the Europa League and are still in Europe beyond Christmas which is a massive boost here for these unbelievable fans at Celtic Park."
Catch Barcelona v Celtic from 7pm on Tuesday on Sky Sports 2 HD.