Trump's fortunes changed for the 2008–09 season when he reached the venue stages of the first four events. At the Grand Prix, he benefited from Graeme Dott's withdrawal before defeating Joe Perry 5–2 in the last 16, despite Perry feeling that he had outplayed Trump, who himself admitted to not having played well. Then came the biggest win of his career so far, when he defeated Ronnie O'Sullivan 5–4 to reach the semi-final, in which he was himself defeated 4–6 by John Higgins. He beat double world champion Mark Williams to qualify for the 2008 Bahrain Championship. He won a qualifying event in 2008 to gain entry into the 2009 Masters as the only qualifier, but was defeated by Mark Allen in the first round. He again failed to reach the main stage of the World Championship, losing 8–10 to Stephen Lee in the final qualifying round, having led 6–3. Lee noted that Trump had not followed the custom of apologising for fluked shots during the match, and concluded "all I've heard about for the last five years in my area is how good he is, and he is good .. but he's blown a 6–3 lead today and hopefully that will stick with him for a while yet." Trump ended the season in the Top 32 of the rankings for the first time. He was coached for a short time by Tony Chappel.