 The following year he settled into the side and, playing alongside the likes of John Charles and John Toshack, he finished as the club's top scorer with a total of 23 goals.In March 1967, Johnston played in a benefit match for victims of the Aberfan disaster against Arsenal and scored twice against the London club, which persuaded them to offer £20,000 to Cardiff to sign him.He made his debut for Arsenal on 19 August 1967, against Stoke City, and made 17 appearances in his first season, 1967-68.