Winstone turned professional in 1959 and was managed by former European welterweight champion,
Eddie Thomas. Winstone made his professional debut in February 1959 at
Wembley Stadium, London, when he beat Billy Graydon on points over six rounds. He then proceeded to win his first 24 fights, at which point he was considered ready for a shot at the British featherweight title. In May 1961 he fought
Terry Spinks the holder of the British featherweight title at the
Empire Pool, Wembley. He out-boxed Spinks, forcing him to retire after ten rounds, and so claimed the British title. He continued to win all his contests and in April 1962 he defended his title against Derry Treanor, at the Empire Pool, winning by a technical knockout in the fourteenth round. The next month he defended his title against Harry Carroll in
Cardiff forcing him to retire after six rounds. His first defeat came in November 1962 his 35th fight after 34 straight wins. He was beaten by Leroy Jeffery, an American featherweight, by a technical knockout in the second round after having been knocked down three times. In January 1963, he defended his British title for the third time, defeating Johnny Morrisey by a technical knockout in the eleventh, in Glasgow. In July 1963, he challenged for the European featherweight title, fighting Italian holder, Alberto Serti in Cardiff. Winstone won the title when the referee stopped the fight in the fourteenth round. One month later he defended both titles against Billy Calvert in
Porthcawl, winning on points over fifteen rounds. In December 1963 he again defended his titles against John O'Brien, again winning on points. In January 1964 he suffered only his second defeat in 45 fights, losing to the American, Don Johnson. In May 1964 he defended his European title against Italian, Lino Mastellaro at the Empire Pool, winning by a technical knockout in the Eighth round. In January 1965 he defended his European title again, against Frenchman, Yves Desmarets in Rome. He won on points over fifteen rounds. ==World title fights==