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 the final and went on to lose the final 4–10, receiving the runner-up prize of £90,000. In the World Open, Selby defeated Alan McManus 5–1 in the quarter-finals and Marco Fu 6–4 in the semi-finals, but lost 6–10 in the final to Shaun Murphy. At the World Championship, Selby beat Michael White 10–9, Ali Carter 13–9, and Alan McManus 13–5 to reach his first semi-final at the Crucible since 2010. He played world number one Neil Robertson in a repeat of the UK Championship final, and this time came out a 17–15 winner in a match described by commentators as