Former world champion Stuart Bingham took a 5-3 lead over Ali Carter in the first session of the Masters final.
Carter, who is only in the tournament because Ronnie O’Sullivan decided not to enter, started with a century as the first four frames were shared.
But 2015 Crucible winner Bingham, 43, took control by winning three of the next four, including an important eighth frame after a 40-minute battle.
The best-of-19 final concludes from 19:00 BST on BBC TV and online.
With many of the favourites falling in the early stages of the competition, these two unfancied players from Essex, who competed against each other in the junior county league, have seized advantage to reach their first Masters final.
World number 17 Carter made the perfect start with a superb 126 break and also complied 56 and 93 for a 3-2 advantage.
The 40-year-old should have taken the sixth frame which could have been a major turning point. With a deficit of 69 points and only 67 remaining on the table, he got the snooker required but then missed the final brown, allowing Bingham to pinch the frame on the black.
World number 14 Bingham made 50 in the next, as well as snatching the last of the session for a two-frame cushion heading into the evening.
Play was momentarily halted with Bingham at the table in the fifth frame when someone seemed to have left a ‘whoopee cushion’ device inside the arena which kept emitting off-putting noises. The crowd laughed at the incident but neither player found it funny.