The 47-year-old Welshman recorded the third maximum of his career in the third frame of the match, having lost the first three frames, compiling just 17 points in the process.
After potting the black Williams began sauntering off for the mid-session interval before being called back to accept the congratulations of his Australian opponent.
Williams made his first competitive 147 break against Robert Milkins at the 2005 World Championship, and his second at a minor event in 2010. It is already the seventh maximum break of the season.