John Robertson had played for Scotland at Schoolboy and Youth levels and for Drumchapel Amateurs before joining Forest in May 1970, making his debut for the team in October 1970. Although he was an infrequent member of the first team as a midfielder up to 1975, and was on the transfer list when Clough became manager, Robertson became a key player as a left winger under Clough and appeared in 243 consecutive games between December 1976 and December 1980. He scored the winning goal, a penalty, for Forest in the 1978 Football League Cup Final replay against Liverpool. He also scored the winner in the 1980 European Cup Final against Hamburg and provided the cross for the winning goal in the 1979 European Cup Final, scored by Trevor Francis, against Malmö FF.
Brian Clough, Robertson's manager at Nottingham Forest, was quoted as saying "John Robertson was a very unattractive young man. 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." In his autobiography, Clough noted that "Rarely could there have been a more unlikely looking professional athlete. He was a scruffy, unfit, an uninterested waste of time but something told me he was worth persevering with. He became one of the finest deliverers of a football I have ever seen – in Britain or anywhere else in the world – as fine as the Brazilians or the supremely gifted Italians." Robertson's captain at Forest, John McGovern, later said that "John Robertson was like Ryan Giggs but with two good feet, not one. He had more ability than Ryan Giggs, his ratio of creating goals was better and overall he was the superior footballer", whilst Forest coach Jimmy Gordon rated Robertson as a better player than Tom Finney and Stanley Matthews, claiming that he "had something extra on top."
There is a piece in “I believe in miracles”, the film about Notts Forest’s double European Cup-winning side, in which Brian Clough is discussing facing Hamburg in the second of those finals. During the interview the talk turned to Manny Kaltz, Hamburg’s right back, who was considered to be one of the best defenders in Europe. Instead of Clough’s concern deepening, a smile grows across Brian’s face, and he says, “We’ve got a little fat guy who will turn him inside out, a very talented, highly-skilled, unbelievable outside left”. Most people agreed that John Robertson was Clough’s favourite player and probably the best to ever play for Forest. Robertson had been an overweight and rather directionless midfield player when Clough arrived in 1975, one that Forest’s previous manager had nearly sold to Partick Thistle. Clough and Taylor saw something in him, put him on the left wing and turned Robertson into a magician. Robertson might have looked like a shuffling nonentity off the pitch, scruffy and overweight, but on it he was delicate, almost dainty as he approached full-backs with subtlety and purpose. He wasn’t a player with a plethora of skills, nor was he one with any pace to speak of, but he was still a magician, a hoodwinker of defenders who seemed to treat every encounter with a full-back as a confidence trick. One that they would fall for every time.
Nottingham Forest lift the League Cup following a 3-2 win over Southampton with John Robertson holding a tankard 3rd from the right. The late 1970s were a golden time for Nottingham Forest. Under Brian Clough and Peter Taylor they won the League in 1977, the European Cup in 1979 & 1980 and the League Cup in 1978 & 1979. Much of this success was down to John Robertson’s wizardry on the left wing and the vision of Clough and Taylor in discovering and nurturing his fantastic talent.