Day advanced to the quarter-final stage of the Shanghai Masters by overcoming Neil Robertson and Mei Xiwen both 5–2 and lost 5–3 to Mark Selby. He won the first four frames against Mark Allen in the third round of the UK Championship, but went on to lose 6–5. His second quarter-final of the season came at the German Masters and he was defeated 5–2 by Martin Gould. At the World Grand Prix, Day overcame Stuart Bingham, Michael White and Shaun Murphy all 4–2. In the semi-finals he was 4–3 down to Marco Fu, but recovered from needing four snookers in the eighth frame to level and went on to win 6–4. In Day's first ranking event final since 2008 he was 9–3 behind Barry Hawkins and, though he pulled it back to 9–7, he was defeated 10–7. Day lost in the final of the non-ranking Championship League 3–0 to John Higgins. A 4–2 win over Neil Robertson saw Day play in the semi-finals of the Gibraltar Open and he was beaten 4–2 by Judd Trump after leading 2–0. Day was a seeded player for the World Championship, but lost 10–4 Xiao Guodong in the first round and once again blamed his lack of concentration for the early exit.