Donaldson won four matches to meet Ding Junhui in the opening round of the Shanghai Masters and had leads of 3–1 and 4–3, before Ding forced a deciding frame. Donaldson had a chance to pull off the shock, but missed a simple black and Ding won through. Donaldson reached the last 16 of both the European Masters and Northern Ireland Open, losing 4–3 to Anthony McGill and 4–2 to Hossein Vafaei respectively. At the Welsh Open he beat Jack Lisowski 4–1, Mark King 4–2, Jimmy Robertson 4–0 and Mark Davis 4–3 to reach the quarter-finals. He faced Zhou Yuelong, who was also appearing at this stage of a ranking event for the first time and Donaldson thrashed him 5–0. Donaldson pulled back from 4–1 down against Judd Trump in the semi-finals to 4–3, but lost 6–3. He won £20,000 for reaching the final four and was placed 65th in the world at the end of the season, the third highest of all the players who began the year on zero ranking points.