Skipper Scott Brown admits the memory of their AEK Athens exit last season will drive Celtic on in their bid to reach the Champions League this time around.
The Hoops were knocked out in the third qualifying round by a limited Greek side after a 1-1 draw at Parkhead was followed up by a 2-1 defeat in the return game.
The Scottish champions had to settle for a place in the Europa League through the play-off, reaching the last 32 before losing out to Spanish outfit Valencia.
Neil Lennon's side, who completed the domestic treble treble in May, begin their quest to make the group stages of European club football's elite competition this season with a tie against Sarajevo, the first leg of the first qualifier taking place the Asim Ferhatovic Hase stadium on Tuesday night.
Brown, 34, speaking at Celtic's hotel in Bosnia and Herzegovina, recalled the disappointment of last year and how it will, he hopes, energise the side in their efforts.
"What happened in Athens last year was hard to take for everyone," said the midfielder.
"We thought we were the better team over two legs but we just couldn't get the ball in the back of the net.
"We played some great football and were just unlucky with a few injuries as well, a couple of the lads couldn't quite make the game.
"It is always on the back of your mind. We just couldn't get it over the line.
"That's the things that drive us on to try to get into the Champions League.
"It's huge for me. You want to play against the best players and best clubs in the world. That's why I signed for Celtic, to play in these kinds of competitions.
"It's huge in terms of money, sponsorship and putting ourselves out there for people to see what a top-quality team and club we are, but we need to make sure we are there in the first place.
"A lot of the players come to Celtic because see Champions League nights like when we were playing Man City and PSG, and we want that atmosphere again at Celtic Park.
"We want to be in the Champions League and we think this club deserves to be in the Champions League, so we need to make sure we make the club proud."
