In the first round of the 2015 Australian Goldfields Open, Neil Robertson fought back to 4–4 after Selt had been 4–0 up. The deciding frame lasted 55 minutes and Selt took it on the final blue and then edged past Mark Joyce 5–4 to reach the quarter-finals of the event for the third time. He was unable to feature in his first ranking event semi-final as Martin Gould comfortably beat him 5–1. However, Selt rose to a career-high 27th in the world rankings soon afterwards and credited his improvement in play to his coach Chris Henry, his mentor Stephen Hendry, as well as his own personal fitness. He lost 5–4 on the final black to Judd Trump in the second round of the Shanghai Masters. Despite describing his play as pretty terrible, Selt reached the fourth round of the UK Championship and recovered from 3–1 down against Luca Brecel to knock him out 6–4. He also said that his 6–0 loss to Ronnie O'Sullivan a year earlier had improved him as a player. In his first UK quarter-final he was defeated 6–1 by Mark Selby, but the £20,000 in prize money he earned is the biggest of his career so far. O'Sullivan beat Selt 3–0 in the semi-finals of the non-ranking Championship League. He failed to qualify for the World Championship after losing 10–9 to Mitchell Mann in the second qualifying round. His ranking over the course of the season rose five places to world number 25.