When Celtic lifted the European Cup in 1967, all but one of their 15-man squad had been born within 10 miles of the club's home ground. Forty-five years on, another famous and indelible mark was etched in Celtic's history by a distinctly more cosmopolitan group of players.

Not that nationality will matter one iota to the Celtic support, who will rightly hail the heroes who defeated Barcelona on Champions League business on Wednesday night, but only one of the starting XI, Charlie Mulgrew, was Scottish-born.

Albeit player values have been warped by the ability to move under freedom of contract, a glance at Celtic's successful line-up in comparison to their Catalan opponents paints a striking picture. It also endorses just how impressive Celtic's shock victory, and general performance, actually was. Earlier in this campaign, Celtic had held their own in the Camp Nou and scored three times in victory at Spartak Moscow.

Five of the starting Celtic team – Adam Matthews, Kelvin Wilson, Mulgrew, Mikael Lustig and Joe Ledley – moved to Glasgow under freedom of contract. One, Miku, is a loan signing. Fraser Forster, Efe Ambrose, Kris Commons, Victor Wanyama and Georgios Samaras did command transfer fees but that figure, in total, is no more than £6m. Tony Watt, an 18-year-old who stepped from the bench to score Celtic's crucial second goal, cost £50,000 from Airdrie United.

Paltry figures, in other words, compared to the vast sums which are now thrown around by the clubs who prominently feature year on year in the Champions League. No Celtic player earns more than £1.5m a year as a basic wage; Barcelona's average annual salary is reported to be about £5m.

Celtic's ability to perform with distinction at Champions League level highlights how successfully they have recruited young players from far afield. Under Neil Lennon's predecessor, Tony Mowbray, too many players arrived at Celtic who lacked an ability to handle the pressures of Old Firm life.

John Park, Celtic's football development manager, is the man credited with sourcing the clutch of players who could now be sold on for considerable profit. During Park's time at Hibernian, the club produced and sold a number of exciting young players.

Wanyama is Celtic's case in point; a 21-year-old athletic midfielder, with no shortage of passing talent, who cost just £900,000 from Beerschot in Belgium. Amid interest from top English clubs, Celtic's manager Lennon spoke of Wanyama being valued at £25m. The Kenyan's display against Barcelona offered food for thought to those who scoffed at Lennon's words.

Wanyama is an example of the specific markets Celtic have targeted; those with affordable young players – in terms of transfer fee and salary – whom bigger clubs may be reluctant to take a chance on; other smaller leagues, essentially, which offer potentially hidden gems.

For the players, there is the obvious lure of Champions League football and a decent shop window towards the English top flight.

The full-back, Emilio Izaguirre, arrived from Honduran football for £600,000 after Celtic launched a specific scouting focus on the 2010 World Cup. Beram Kayal signed from Maccabi Haifa and Ki Sung-yueng, who was subsequently sold to Swansea City for three times the £2m Celtic paid for him, joined from FC Seoul. Commons, at just £300,000, represents one of Celtic's best value for money purchases of recent times.

Gary Hooper would have played against Barcelona and was poised to have joined Forster in the England squad named for next week's friendly in Sweden, had the striker not picked up a hamstring injury. Alan Thompson, in 2004, is the only player to win an England cap while employed by Celtic.

Lennon instantly took to Hooper and made him a priority signing after watching him play for Scunthorpe United, with Celtic's manager taken by the scrapping qualities which are valuable when seeking Scottish Premier League goals. Hooper has surpassed Lennon's aspirations and justified his faith; the 24-year-old is now tipped for a lucrative move to England's Premier League.

At face value, it is curious that Forster was overlooked for so long at Newcastle United. The goalkeeper found himself placed behind Shay Given, Steve Harper and Tim Krul in the pecking order at St James' Park.

Newcastle had decided Krul was a better prospect than Forster long before the latter made a £2m move to Celtic. It is in European matches over the past two seasons that Forster's form has been especially impressive. One Catalan newspaper on Thursday morning dubbed Forster "La Gran Muralla", "The Great Wall".

For Lennon, too, there has been an epic turnaround. Last October, Celtic found themselves 3-0 down within 45 minutes at Kilmarnock with their manager, by his own subsequent admission, wondering how to compose his resignation letter. Lennon's team recovered to claim a draw that day, won the championship and are now making positive inroads in Europe. For the manager, whose own talent may well have been understated in the past, that is an achievement worthy of wide recognition.