John Robertson, who has died aged 72, was once described by legendary Nottingham Forest manager Brian Clough as "the Picasso of our game".

Robertson was languishing at the City Ground until Clough arrived in January 1975, releasing the brains and talent that had been hidden behind the Scot's often unkempt appearance to magnificent effect in Forest's great team of the late 1970s and early 1980s.

Indeed, the left-winger was widely regarded as the most influential player in a team that won the First Division title and the League Cup in their first season after winning promotion in 1977-78.

This, incredibly, was only the start.

Forest followed this up with the even more remarkable feat of not only winning the European Cup in 1979 against Malmo, when Robertson provided the perfect left-wing cross for Trevor Francis' decisive header, but retained it the next year when his goal beat SV Hamburg at the Bernabeu in Madrid.

Robertson was also at the centre of the bitter split between Clough and his long-time managerial partner Peter Taylor in 1983.

Clough never forgave Taylor, who was by then managing Derby County, for signing Robertson on a transfer with a fee to be decided by a tribunal, without informing him of his plans.

To Clough's great regret, the rift was never healed before Taylor died in 1992, aged 62.

Clough often made teasing mention of Robertson's scruffy appearance and knew about his smoking habit, but regarded it as all worthwhile for the magic he provided with his two-footed touchline-hugging brilliance, measured crossing delivery and his knack of scoring crucial goals.

Robertson had played for Scotland at schoolboy and youth level before joining Forest as a teenager in 1970. He had failed to make an impact until Clough's appointment, but the great manager saw something he could nurture.

In his autobiography Clough wrote: "Rarely could there have been a more unlikely looking professional athlete... scruffy, unfit, uninterested waste of time... but something told me he was worth persevering with and he became one of the finest deliverers of a football I have ever seen."

He also wrote: "If one day, I felt a bit off colour, I would sit next to him. I was bloody Errol Flynn in comparison. But give him a ball and a yard of grass, and he was an artist, the Picasso of our game."

Clough was idolised by Robertson, who said: "I knew he liked me but I loved him. I wouldn't have had a career without him."

Robertson played in 243 consecutive games between December 1976 and December 1980, and despite the big-name buys such as England goalkeeper Peter Shilton and Francis, Britain's first £1m footballer, he was the player who made Forest tick.