TO become a successful goalkeeper you need the eyes of a hawk, reflexes of a cobra, courage of a lion and skin of a rhino.

Fortunately for Celtic, Fraser Forster is possessed of all these qualities, as his elevation to the full England squad and the interest being shown in him by big clubs south of the border confirm.

Indeed, the towering presence of Forster is one of the main reasons Celtic are looking forward to competing in the last 16 of the Champions League for the first time in four years,

The mid-season break has allowed the 6ft 6in public schoolboy from Hexham to reflect on how perceptions of him have been transformed in the past year. His struggle to deal with the ball at his feet, a few shaky moments in games against Rangers, the odd error, such as the one which cost Cetic a clean sheet in Rennes, no longer provide ammunition for the snipers taking cheap shots at the 24-year-old, who had two loan spells at Celtic before his transfer from Newcastle United was made permanent last summer.

The flying save from Eggert Jonsson's penalty in the dying minutes of a tense match against Hearts in December 2011 has been identified as moment his Celtic career took off as his confidence soared in tandem with his reputation.

As he took a break from enjoying working with the sun on his back in Marbella, Forster said: "I wasn't particularly aware of it [getting stick initially]. I didn't pay that much attention to it. I always had the belief you need. I broke the clean sheet record in the first season at Celtic and did it again in the second. From a keeper's point of view, you can't do much more than that. Maybe being a loan player didn't really help. With what we do, we get a lot of criticism. You've just got to try to ignore that. It helps if you've got good people around you, ones who believe in you."

Lennon has always been in that camp, even when what seemed to be the manager's obsession to secure Forster as his No.1 goalkeeper was being openly questioned by those who did not rate him anywhere near as highly.

Now, large helpings of humble pie are being consumed. Alan Pardew, the Newcastle manager, was one who did not see Forster as good enough to be first choice at his club, let alone a challenger to Joe Hart in the national set-up. Pardew's views on Scottish football were equally as uncomplimentary, but Forster is not in the business of trying to make anyone look silly.

"It's his opinion," he said. "Until you see Celtic in person – how big a club it is – people maybe don't understand. I could see it. The good thing about it was it was my decision. I'm delighted with the way it's worked out. Stevie Woods [goalkeeping coach] has played a huge part in how I've progressed. We've worked really hard on every aspect of the game."

The rewards for which are now coming reaped, in the form of recognition from respected judges across Europe, and in the more tangible form of medals. It is consistent form which is expected to see Forster retain his place in Roy Hodgson's England squad for next month's friendly against Brazil, another reassurance that playing in the Clydesdale Bank Premier League is not akin to buying a ticket to obscurity.

Forster did not hesitate when asked if he believes he can achieve all he wants as a Celtic player: "I don't see why not. We've done well in the Champions League, so, at the moment, everything is going to plan. We'll have to see, over the next few months, and go from there. What's good with the Champions League is the level of exposure you get UK-wide."

Looming large on that horizon are the ties against Juventus, whose keeper, Gianluigi Buffon, has been among those praising Forster. "You could have worse people commenting on you," he laughed. "He's won everything, World Cups, the works. He even pulls off wearing a hair clip."