The first qualifier ever to make the Scottish final, Paxton will face fellow countryman Greg Harlow, the former world champion from Ely who edged out Welshman Robert Weale, the Commonwealth Games singles gold medallist, in one of the closest games on record.
The Co-operative Funeralcare Scottish International Open features all but one of the top 16 indoor bowlers in the world, joined by qualifiers from the UK, Australia, South Africa, USA, Canada, Hong Kong and Israel. The championship has attracted live coverage on BBC TV Scotland all week, through to the final on Saturday.
Paxton has been in ominous form in Perth and reached the semi-finals without dropping a set. But King, the world No5 who beat the Devonian at the same stage a year ago, led in both sets.
However, from 3-5 down in the first, and 1-4 behind in the second, the 33-year-old world No18 from Exeter took complete control of proceedings, preventing King from scoring further before closing out the game 10-5, 9-4.
At one shot down going into the eighth end of the first set, King scored a front toucher with his first bowl – but Paxton ended up by winning the end by four shots to bring the set to an early close!
"It's third time lucky for me against Mervyn in semi-finals," said a delighted Paxton afterwards. "But I struggled with my first couple of bowls and didn't put him under any pressure.
"The four shots I got on the eighth end was a shock as I had fully expected Merv to get in among them.
“To be honest, I wasn’t overly pleased with the way I played today but I did what I had to do to get over the line - and it was very nice to break my semi-final hoodoo,” added the Exonia club star.
King, the 2006 world champion, admitted that he got off to a good start: "But at the end of the day, he played better than me," explained the 45-year-old from Norfolk.
"Rob's been fighting around for a long time – and thoroughly deserves his place now in the world top 16."
The other semi-final was full of drama right up to the final bowl of the third tie-break end. Third seed Harlow had reached the last four as anticipated – though survived his previous two rounds only after tie-breaks.
Weale, however, was the 11th seed and made his breakthrough in the previous round after ousting Scotland's world champion and world number one Paul Foster, the No2 seed.
And the 48-year-old former world No6 from Hereford led 9-3 in the first set and 6-2 in the second and looked to be heading for his first WBT final since January 2009.
But Harlow contrived to tie both sets and, after sharing the first two ends of the tie-break, clinched the third end with his final delivery to record an unexpected 9-9, 7-7, 2-1 victory.
"That was really tough – and, to be honest, I was playing desperation bowls most of the time," admitted Harlow, the world No2. "I can't believe I was able to tie both sets.
"In fact, I feel I totally mugged Robert. Somehow I sneaked through."
But Weale felt no ill-feeling: "I only have myself to blame – I should have closed out the sets," said the Welsh international.
When asked about the final, Harlow added: "I've played Robert quite a few times, but from what I've seen here, he seems to be playing better than ever.
"I'll have to raise my game if I'm going to beat him."
RESULTS: The Co-operative Funeralcare Scottish International Open, Perth, Scotland
Semi-finals:
[Q] Robert Paxton (ENG) bt [1] Mervyn King (ENG) 10-5, 9-4
[3] Greg Harlow (ENG) bt [11] Robert Weale (WAL) 9-9, 7-7, 2-1
Saturday 12 November:
2.00pm: Final
