He made his breakthrough in the 2006–07 season. After finishing top of his group at the 2006 Grand Prix's round robin stage (he lost only one match: his opener against Nigel Bond by 2–3), Robertson then beat Ronnie O'Sullivan 5–1 in the quarter-finals of the event. So he went on to the semi-finals, being only the fourth Australian ever to do so in a ranking event. He beat Alan McManus 6–2 in the semis, to reach his first major final, where he faced a fellow first-time finalist, the unseeded Jamie Cope, whom he beat comfortably by 9–5 to win his first ever professional ranking tournament. The win earned Robertson £60,000, his highest amount of money earned in one tournament.