Mark Selby with a shock 3–5 defeat to Andrew Pagett in the qualifying rounds of the 2013 Wuxi Classic. The tournament was the first to use a new format that required top-16 players to compete in qualifiers. In minor-ranking tournaments, Selby was runner-up in the Yixing Open, where he lost 1–4 to Joe Perry, and the Rotterdam Open, where he lost 3–4 to Mark Williams. He won the Antwerp Open, defeating Ronnie O'Sullivan 4–3 in the final. In December, in the seventh frame of his UK Championship semi-final against Ricky Walden, Selby compiled snooker's 100th officially recognised maximum break in professional competition.
Mark Selby from 5–1 behind in the first round, Mark Williams 6–1 in the quarter-finals, and Graeme Dott 6–5 from 4–1 and 5–4 down in the semi-finals. He then defeated defending champion Neil Robertson 10–6 in the final. He reached the quarter-finals of the German Masters, but lost 1–5 against Barry Hawkins. He lost in the last 32 of the Welsh Open 0–4 against Joe Perry, and lost his number one position to Trump. Selby then reached the quarter-finals of the World Open, but lost 3–5 against Neil Robertson. At the China Open, Selby became only the fourth player in history to