It is impossible to overstate the importance of Tommy Gemmell to Celtic's storied history.

Without the intervention of the left-back, who has died at the age of 73 following a long illness, the team which went on to become the Lisbon Lions may never have achieved the crowning glory of their 1967 European Cup final triumph.

Up against an ultra-defensive Inter Milan, Jock Stein's side - all born within a 30-mile radius of Glasgow - found themselves a goal down after just seven minutes.

Read more: Tributes flood in for Tommy Gemmell after Celtic announce death of Hoops great

The Italians, managed by Helenio Herrera, set up the "catenaccio" - the door bolt - determined to frustrate the Hoops.

For almost an hour they held on for dear life - until Gemmell stepped forward.

Ignoring strict orders from Stein that one of his full-backs must hang back at all times, the Lanarkshire lad raced upfield to step on to a cutback from right-back Jim Craig.

His strike tore past Inter goalkeeper Giuliano Sarti and sent the Hoops on their way to glory, with Stevie Chalmers' late winner ensuring they became the first British side to be crowned champions of Europe.

It was said to be a victory for football, with Celtic's attacking instincts overcoming Inter's joyless style.

Speaking in 2008, Gemmell recalled his part: "The theory was that I stay back. But it so happened that Inter had so many players back behind the ball that I didn't need to stay back.

"I started screaming to get a cutback - and the rest his history."

He later said: "Winning the European Cup was something that happened to the likes of Real Madrid, Benfica and Inter Milan.

"Then along came some upstarts from Glasgow and we were crowned the best in Europe. The warm tingle at the memory of that day will never leave me.

"Coming back from a goal down to Inter Milan, who had won the trophy two out of the previous three years, and to triumph 2-1 was just so special."

Gemmell was born on October 16, 1943, in his grandmother's house in Motherwell, and spent his early years living there. One of four children to father Alfie, a steelworker at the Dalziel plant, and mother Margaret, the family moved to Craigneuk, near the Lanarkshire town's border with Wishaw, when he was seven.

Read more: Tributes flood in for Tommy Gemmell after Celtic announce death of Hoops great

An eight-year-old Gemmell played his first organised game for Craigneuk Primary School wearing wellies, but was soon given a pair of second-hand boots that were two sizes too big.

He represented Wishaw High School and also managed to deliver newspapers before lessons and groceries afterwards, combining two part-time jobs with playing for Craigneuk team Meadow Thistle.

A self-confessed Motherwell "fanatic", Gemmell hoped an appearance for a Lanarkshire amateur select at Fir Park would win him a deal with his boyhood heroes. Instead, Gemmell, who had left school at 16 to become an apprentice electrician in the Ravenscraig steelworks, got a knock at the door from Celtic.

He signed provisional forms in October 1961, immediately being farmed out to Wishaw-based Junior side Coltness United. On the same night, another teenager called Jimmy Johnstone signed for Celtic. The two future European Cup winners got on the same bus from Parkhead back to Lanarkshire, Johnstone getting off first at Viewpark.

Gemmell made the conversion from winger to full-back before his Celtic debut in January 1963 but never lost his attacking instincts.

In the days when full-backs rarely crossed the halfway line, Gemmell helped give Stein the extra dimension he was looking for when he took over from Jimmy McGrory in 1965.

His forward runs and confidence meant Celtic could build their forays from the back and he always had an eye for goal. He amassed 63 goals in 418 appearances in green and white.

By netting against Feyenoord in 1970, he became the first British player to score in two European Cup finals and he was an expert penalty-taker, missing just three attempts from 34.

Read more: Tributes flood in for Tommy Gemmell after Celtic announce death of Hoops great

During his decade-long Hoops stint, Gemmell added six league titles, three Scottish Cups and four League Cups to the winners' medal he collected in Lisbon.

He was also capped 18 times for Scotland - including the 3-2 win over world champions England in 1967.

But his talents were appreciated way beyond his homeland.

In their Christmas poll of 1967, France Football magazine ranked him the sixth best player in Europe. Three years later, sports journalists from Hungary and Brazil - nations renowned for their attacking style - voted him the best right-back in the world.

Gemmell's time at Celtic came to an end in 1971 after he fell out of Stein's favour following a number of disciplinary indiscretions but he would move on to Nottingham Forest, where he spent two years playing alongside future Celtic boss Martin O'Neill.

After a short stint in the United States with Miami Toros he returned to Scotland to sign for Dundee in 1973 and soon skippered his new side to victory in that season's League Cup final - against Celtic.

Retirement followed in 1977 but he remained on Tayside to manage the Dark Blues for three years, leading them to the First Division title in 1979. He rounded off his career with two separate, year-long stints as Albion Rovers boss.

Gemmell, who worked as a financial advisor after his full-time career in football ended, is survived by wife Mary, son David and daughter Karen.