semi-finals. At the World Championship, Selby defeated debutant Jordan Brown 10–6 in the first round, Noppon Saengkham 13–12 in the last 16, and Neil Robertson 13–7 in the quarter-finals. In the semi-final, he met Ronnie O'Sullivan, who took a 5–3 lead after the first session, but Selby won the second session to take a 9–7 lead. During the third session, he established a 13–9 advantage before O'Sullivan won the last two frames of the session. Selby then took a 16–14 lead, leaving himself one frame away from his fifth World Championship final, but he lost the final three frames of the match. After the game, Selby accused his opponent of being "disrespectful" after O'Sullivan had played several hit-and-hope shots while being snookered. Selby finished the season as world number four. 2020–21 season After the delayed start to the new season, Selby won his 18th ranking title at the 2020 European Masters in September, defeating Martin Gould 9–8 in the final. The score was level at 4–4 by the end of the afternoon session, despite Selby taking an early 4–0 lead. The two players were evenly matched throughout the evening session, but Selby eventually won the match in the final-frame decider with a break of 72. The win moved Selby to a joint sixth place, alongside Neil Robertson, on the list of players with the most world ranking titles. In October, he began the defence of his title at the 2020 English Open. After defeating Fan Zhengyi, Chang Bingyu, Liang Wenbo, Hossein Vafaei and Zhou Yuelong, he lost 5–6 to Robertson in the semi-finals. Despite losing the title, Selby retained the number one spot in the one-year ranking list. He also progressed through the first two group stages of the ranking Championship League tournament. In the third group stage, although he beat Judd Trump 3–0, he lost 1–3 to Zhou Yuelong and 0–3 to Zhao Xintong, finishing at the bottom of the group. At the Champion of Champions tournament in November, Selby recovered from 0–4 and 3–5 behind, winning the last three frames of his quarter-final match against Kyren Wilson to progress 6–5, only to be defeated by Robertson in another final-frame decider at the semi-final stage of the competition. In December, after yet another loss to Robertson at the quarter-finals of the UK Championship, he successfully defended his Scottish Open title, beating Yuan Sijun, Nigel Bond, Mark Joyce, Lyu Haotian,