The 2009–10 season started badly when Williams broke his wrist in a fall at home, less than a month before the Shanghai Masters, the first ranking event of the season. He played in Shanghai despite the injury, but wore a cast on his wrist because its removal could have caused long-term damage. There he won his first round match against Joe Swail 5–3, but lost in the next round against John Higgins 1–5. In the Grand Prix he secured wins over Stuart Bingham, Stephen Hendry and Robert Milkins on his way to the semi-finals. Despite racking up a 142 (the highest break of the tournament) in the first frame against Ding Junhui, he lost 1–6.