The 19-year-old full-back has penned a four-year deal with the Glasgow giants after quitting Manchester United.
The Swiss youth international admits the lure of potential Champions League action and the chance to work with boss Ronny Deila were all decisive factors in his move north.
But he revealed it was the words of Barcelona's superstar duo following the Catalan outfit's 2-1 Parkhead defeat in November 2012 which convinced him to kick-start his career north of the border.
Xavi claimed he had "never seen anything like the Celtic fans" following their side's famous win, while four-time Ballon d'Or winner Messi insists the Hoops' home ground produces the best atmosphere anywhere on the continent.
Janko said: "I'm looking forward to the atmosphere and the fans hopefully on a Champions League night or even league days.
"Even players like Messi and Xavi dream about the atmosphere at Celtic Park so I'm looking forward to that.
"I was quite happy to stay at Manchester United but Celtic is hard to resist
I'm in the first team everyday I'll train with them and hopefully get in the first XI
At Man United it's a bit more difficult.
"Celtic is a massive club in Europe
I think all over the world people know Celtic, people know the supporters
They have a big stadium too, it's huge.The Champions League is every kid's dream and it is definitely a plus I think."
The Hoops will have to fork out a compensation fee for Janko - who watched his new team-mates for the first time on Thursday night as they kicked-off their pre-season preparations with a 2-0 win over Den Bosch in Paisley - after he turned down United's offer of an extended stay.
Despite being rated highly by the Old Trafford coaching staff, the defender failed to make a first-team appearance for the Red Devils after being signed by former boss Davie Moyes in 2013.
But he did feature 10 times under ex-Hoops manager Neil Lennon during last season's loan switch at Bolton last season.
However, the former FC Zurich youngster is eager to move on from his frustrating United stint with his new side.
"Manchester United is a big club too and I had a great time there," he said
"But I thought I needed a new challenge and here I am.
"United is definitely a hard place to leave because it's one of the biggest clubs in the world.
"But it's hard to leave any place, not just United.
"Am I right to fight for a place here at Celtic now? Yeah definitely, that's what I'm here to do
To get more game time
If I push more, my other team-mates will push more and the whole level gets better
That's good for the whole team.
"I have recently played more in midfield but the manager told me he sees me more as a right-back than a right midfield."
The east end of Glasgow has become a regular stopping point in recent years for ambitions players hoping to make their way to the riches of the Barclays Premiership.
But Janko is more interested in banking the advice of Hoops boss Deila.
Asked if he saw Celtic as a stepping stone to England, he replied: "No
I've signed here for four years and I want to do my best
I hope I can please the fans with my performances.
"I'm a Celtic player now and my head is here
I'm not looking to a few years ahead to go anywhere.
"The manager is a very good coach
He spoke with me about many things
He wants me to work on a lot of things and make me better as a player
That's what he told me and I'm happy to do that."
Source : PA
Source: PA