Steve Davis gave Ronnie O'Sullivan a fright before letting his lead slip to leave the Welsh Open tied at 4-4 in Cardiff this afternoon.
Davis, looking for his first ranking title since winning the 1995 event, claimed a shock 3-0 lead as O'Sullivan struggled to find any sort of rhythm.
A 40 clearance in the opening frame, followed by a run of 74, put the 46-year-old 2-0 ahead and Davis pieced together a 42 break to clinch the third.
O'Sullivan claimed the fourth with a break of 58 but lost the fifth when Davis doubled the final black the full length of the table.
Davis was looking good for 5-1 as well but O'Sullivan potted a great long red and closed to 4-2 before ending the session with back-to-back centuries of 125 and 139.
It is the first meeting in a final between the pair since Davis recovered from 8-4 down to beat O'Sullivan 10-8 in the 1997 Wembley Masters.
The six-time former world champion has lost his last six meetings with O'Sullivan, who holds a 10-6 career advantage.
O'Sullivan, the world number three, is searching for his first title since winning the Irish Masters 10 months ago and the 14th ranking tournament trophy of his career.