round of the 2007 World Championship, but lost 10–13 to Ronnie O'Sullivan despite winning six frames in a row at one stage. Robertson started the 2007–08 season poorly, making early exits in three of the first four ranking events, as well as at the 2008 Masters and the 2008 Malta Cup. He did reach the quarter-finals of the 2007 Northern Ireland Trophy though, after wins over Jamie Cope and Ian McCulloch, but there he lost 2–5 to Stephen Maguire. His Welsh Open title defence also ended early, as he was defeated in the last 16 by Ali Carter 5–3, even though Robertson pulled back three frames in a row after being 4–0 down. He finished the season ranked 10th, but outside the top sixteen on the one-year list. 2008–09 season After a disappointing start to the 2008–09 season, Robertson reached the final of the 2008 Bahrain Championship, where he played Matthew Stevens. The match lasted almost six hours in total, with the Australian edging it 9–7. In the second half of the season, during their quarter-final match at the 2009 Masters, Robertson and opponent Stephen Maguire set a record of five consecutive century breaks. Robertson made two centuries and Maguire made three, the latter sealing a 6–3 win over the Australian with his third. Next month, Robertson reached the semi-finals of the 2009 Welsh Open, but lost to eventual runner-up Joe Swail. At the 2009 World Championship, Robertson defeated Steve Davis, Ali Carter and Stephen Maguire to reach the semi-finals of the World Championship for the first time, before losing to Shaun Murphy 14–17, after recovering from 7–14 behind to level at 14–14. 2009–10 season In October 2009, Robertson clinched the 2009 Grand Prix trophy in Glasgow with a 9–4 win over China's Ding Junhui in the final. His semi-final match with defending champion John Higgins was won on the final black of the deciding frame. He also made his 100th career century during the event. Robertson's fourth title made him the most successful player from outside the UK and Ireland in ranking tournaments, although Ding Junhui equalled his total at that season's UK Championship. On 1 April 2010, Robertson made the first official maximum break of his career in his second round match in the 2010 China Open against Peter Ebdon. At the 2010 World Championship, Robertson defeated Fergal O'Brien 10–5 in the first round. In his second round