He had not previously recorded a competitive 147 since the 2018 English Open.
He is only the second player to make two 147s in the same match, after Welshman Jackson Page achieved the feat in qualifying for the Worlds in April.
O’Sullivan’s tally of 17 is four more than that of John Higgins, who is a fellow member of snooker’s fabled ‘Class of 92’.
The Englishman, who also enjoyed breaks of 142 and 70 to lead 3-1 at the mid-session interval, was in scintillating form all evening.
While Wakelin made a 125 break on his way to drawing level at 3-3, O’Sullivan’s second 147 of the evening was followed by a 67 and a 134 to round off an imperious display.
He is also in line to claim a two-thirds share of a £50,000 147 bonus with Thepchaiya Un-Nooh, who knocked in the third maximum of the season earlier this week.
In Friday’s earlier last-four match – at a tournament regarded as snooker’s ‘fourth major’ by organisers – Robertson claimed a 6-3 win over Elliot Slessor.
While neither player was at their best, the rejuvenated Australian was always in control and enjoyed two runs of 93 and a 50 as he reached the 39th ranking final of his career.
“The start was crucial today, I could see Elliot was a bit nervous and I was able to use my experience,” said 2010 Crucible winner Robertson.
“To get to the final is huge in terms of ranking points, it means I should be in all of the big events later in the season which makes my scheduling so much easier.
“I took that for granted a few years ago when I was always in the top four. The standard is so high now that I have realised you have to keep your foot down all the time. A lot of hard work has happened to get these kind of results.”
