The Wales midfielder helped the Hoops stun the Catalan giants with an unlikely 2-1 victory in front of almost 60,000 fans at Celtic Park on Wednesday night with momentous goals from Victor Wanyama and Tony Watt making Lionel Messi’s late counter a consolation.
With two Group G games remaining away to Benfica and home to Spartak Moscow, Neil Lennon’s men are on seven points, two behind leaders Barca.
The Scottish champions will guarantee themselves a place in the last 16 with a fixture to spare if they beat Benfica in Lisbon later in the month and the Nou Camp side beat Spartak Moscow.
Speaking at the Scottish Communities League Cup semi-final draw in Edinburgh, where Celtic were paired with St Mirren, Ledley said: “I went home after the game and sat with the family and it didn’t really sink in.
“I watched it on television but you still can’t believe that we have done it, it will take a couple of days, but it was a fantastic achievement.
“Realistically we would probably have thought we would have got no points (from Barca) but what we achieved was fantastic.
Celtic striker Miku insists his summer move to Parkhead was vindicated by a result that is still reverberating around Europe.
The Venezuela international, signed on a year’s loan from Spanish side Getafe, has taken his time to adapt to life in Scotland but he scored his first goal for the Hoops in the 2-2 draw against Dundee United at Tannadice at the weekend.
“Too many people in Spain thought my transfer to Scotland was a backwards step but I don’t think so,” he said.
“It’s not back, it’s a step in the same direction.
“People in Spain will respect football in Scotland more now because Barcelona is probably the best team in history but Celtic beat them in the Champions League.
“It’s a different league and country and I had two months when it was difficult because of the weather, the food and my wife doesn’t speak good English and my baby was sick, but now I am good, I am enjoying it and the manager speaks to me a lot.’’
Celtic legend Henrik Larsson believes the club’s victory eclipsed anything he achieved in the green and white hoops.
Larsson helped Celtic knock the Catalan giants out of the 2004 Uefa Cup — a year after Martin O‘Neill’s team reached the final.
Larsson, who scored 242 goals in 315 appearances for Celtic, said: “It has to be the best one, without a doubt.
“Beating Barcelona with the team they have now has to be the best experience, it beats everything I have been involved in myself.
“But also the way you heard the fans through the television, everyone is raving about the atmosphere. They have to be pleased with that because they were absolutely fantastic again.
“It’s the best result against any team there at Parkhead because you’re playing against the world’s best team.”
Despite losing at Celtic Park Barcelona boss Tito Vilanova is adamant his side will not change their style of play.
Celtic defended deep and narrow, not allowing Barcelona space to play the intricate passes in and around the box which characterise their play.
“We read the game well, we created a lot of chances but we weren’t on target and their keeper was brilliant,” Vilanova said.
“We did what we needed to do in these types of games, we’ve seen this on other occasions. This is the type of football that the Barca fans want to see.”