 His first, brief introduction to tennis came at age six or seven with a week-long tennis camp at the Bramalea Tennis Club in Brampton, followed by weekly hour-long group sessions led by tennis coach Steve Gibson, who recognized his potential. He moved to nearby Thornhill, Ontario soon after, and one or two years passed before he asked his parents if he could play again. His father sought out coach Casey Curtis at the Blackmore Tennis Club in Richmond Hill, Ontario. Curtis was at first reluctant to take on Raonic, but was convinced after Raonic demonstrated his commitment by working with his father and a ball machine daily for two months. Years later, Raonic said he chose tennis because of its "individuality and [because he] felt [he] could train more alone and on a ball machine with [his] dad".
