Mark Tonelli - National and International Debut

National and International Debut

In 1973, at the age of 15, Tonelli competed in his first Australian Age Championships in Hobart, winning the 100 m and 200 m freestyle, and the 200 m backstroke. These results allowed him to swim at the preliminary qualifying trials for the 1973 World Aquatics Championships, where he managed four fourth placings. However, the selectors held another set of trials just before the World Championships, which offered swimmers a final chance to gain selection. Tonelli said "Everyone, except me, knew it was a ploy simply to keep the team on its toes".

Upon returning to Brisbane after the first round of trials, Tonelli tore rib cartilage while participating in judo at high school. The pain of the injury restricted him to swimming backstroke for four months, and his times steadily improved during this period under the guidance of John Rigby at the Valley Pool. At the final selection event, he came second in both the 100 m and 200 m backstroke behind Olympic gold medallist Brad Cooper to earn his international debut. At the World Championships in Belgrade, Yugoslavia, he came sixth in the 200 m backstroke behind East Germany's Roland Matthes, who set a world record. Tonelli self-deprecatingly noted that "I didn't get to see him swim in the final, because I was in the same race five sets of speedos behind".

Tonelli won his first Australian titles in 1974, claiming both the 100 m backstroke and 200 m butterfly; it was his first race in the latter stroke at senior national level. He completed the victories in times of 59.55 s and 2 m 7.30 s respectively. Tonelli also claimed victory as part of the Queensland teams in the 4 × 200 m freestyle and the 4 × 100 m medley relays—it was the first time that Queensland had won the former race. In total, Tonelli had claimed gold medals in three different strokes at his first Australian Championships.