But Joe Ledley predicts there is even better to come from the side built by Neil Lennon.
The Welsh midfielder wants to ensure he is around to be part of it, and is open to the idea of extending his contract which has a year still to run.
Ledley hopes the rest of his team-mates are like-minded, though he appreciates the performance against Barca will have covetous eyes focusing on the players and Lennon himself.
The 25 year-old who arrived from Cardiff on a Bosman at the start of Lennon's reign two years ago, said: "There's more to come – definitely.
"It took us a while to gel. Players were coming and going, but we got there and it's fantastic.
"Hopefully we can keep the group together, bring people in and improve the squad."
Ledley has been a key figure in the turnaround in fortunes of a club which was at a very low ebb just 12 months ago.
They are now the epitome of success breeding success, and he said: "We had belief after the game in the Nou Camp.
"We were unlucky, and, although we knew Barca would have a lot of the ball at Parkhead, it was a fantastic result which will stay with me for the rest of my life. It will go down in history.
"We probably shocked a lot of people. Our form hasn't been great in the SPL, but we knew we had to play at our best against Barcelona. We did that."
No-one more so than Ledley, who was utterly deserving of the jersey given to him by World Cup winner Xavi at the final whistle.
The man who spurned the chance to join Stoke and a move to Italy when he opted to come to Parkhead, feels he has finally delivered the ultimate answer to those who questioned his ambition in moving north.
He said: "People down south always said, 'Why are you joining Celtic?' But I've just proved them wrong – again.
"People are always going to criticise Scottish football for some reason. I think it's a fantastic league.
"To play in the Champions League is a huge honour, too.
"I like winning games, I want to win things and play in the best competition in the world – the Champions League."
He added: "To play in the Europa League last season was fantastic, but we were hungry and wanted more.
"We finally got to the Champions League and it's by far the best moment of my life."