Champions League: Celtic must be at their best against PSG - John Collins
Celtic will need "an exceptional performance" to get a positive result against Paris St-Germain, according to former midfielder John Collins.
PSG are in Glasgow for Tuesday's opening Champions League group match.
And the big-spending French club boast stars such as Neymar, Kylian Mbappe, Edinson Cavani, Marco Verratti, Lucas Moura, Julian Draxler and Dani Alves.
"Celtic will have to be at their best and have a bit of luck as well," Collins told BBC Radio 5 live.
"There is a combination of excitement and fear.
"Certainly the fans are going along with a feeling of excitement.
"The players will probably be on edge but they will be looking forward to it. These are the games you dream of as a footballer.
"Celtic probably don't have a lot to lose. The whole world will expect Paris to win, with the amount of money they've spent."
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PSG shattered the world transfer record to recruit Neymar from Barcelona for £200m and the loan for Monaco's Mbappe has an option to make the deal permanent for £165m.
Argentina internationals Angel Di Maria and Javier Pastore miss out through injury, while Celtic are without defenders Dedryck Boyata and Erik Sviatchenko as well as last season's top scorer Moussa Dembele.
"Of course, Celtic have injuries to contend with in central defence," added Collins, who spent six years as a player with the Scottish champions and was assistant to previous manager Ronny Deila.
"When you're playing against these big teams, you really want your best players on the pitch, so that's a challenge.
"But I'm sure Celtic will put up a good fight.
"They will have to defend very well and take their chances when they come along.
"They will need to be very compact. Guys like Neymar and Mbappe are dribblers who beat people, so it's important that the full-backs don't get isolated with those players in wide areas.
"The midfielders need to get back and help the full-backs.
"Being compact is the key when they don't have the ball, but Celtic have also got to put them on the back foot. The secret is to try and stop the service to these players at the top of the pitch.
"Can Celtic get at them and press Paris? They have such great players all over the park."