Williams lost in the second round of his first two ranking events of the 2014–15 season.&lt;ref name="2014/15"&gt;&lt;/ref&gt; His first quarter-final of the campaign was at the International Championship and he trailed Ronnie O'Sullivan 0–3, before winning five successive frames with a high break of 120. The match went into a deciding frame, which Williams won to beat the five-time world champion for the first time in 12 years. His semi-final match against Mark Allen also went all the way, after Williams had been 4–7 down, and a miss on the final red proved crucial as he was defeated 8–9. He was beaten 2–6 by Stephen Maguire in the third round of the 2014 UK Championship.