Foster, now in his first final since winning his third title in 2005, was in devastating form, wiping out England's semi-final debutant Mark Royal 10-3, 9-2 in the first game at Potters Leisure Resort in Hopton-on-Sea.  

The Scot began to assert his authority on the game from the very start and built up a 6-3 lead.  In the crucial seventh end, Royal was holding two shots to reduce the deficit when Foster played a sensational conversion shot to win a three – claiming the set the following end.

Trailing by four shots going into the sixth end of the second set, the Suffolk left-hander achieved a massive break when he cancelled out a two-shot advantage by Foster to win a single.

"I didn't do much wrong - I hardly played a bad bowl.  It was one of those games you dream of," said 37-year-old Foster afterwards.

"The way Mark was playing, I had to up my game a couple of notches.

"That was very important to me – I've always said that the two rounds you don't want to lose in are the first and the semi-final," added the world number one from Troon in Ayrshire.

"Being in the final again has been a long time coming.  It gets harder and harder – and I'm not getting any younger!

"It will be massive back in Scotland that I am meeting Alex in the final.  We've never played in any final before.

"If I can take that performance into tomorrow, I've got a great chance."

Reminded by Rishi Persad that he said he would need to go up another gear in the semi-final, the BBC TV presenter asked if he had another gear he could go up:  "If I have, I'm not human," responded Foster.

Royal was pleased with his performance:  "I started really well with two bowls right on the jack.  But he drew brilliantly – and he must have hit five runners.

"But he was unplayable, just untouchable," said the 36-year-old from Stowmarket

"It's probably the best anyone's ever played against me.

"But I'm chuffed to bits to have reached the semi-finals for the first time – I don't feel disappointed at all, really," added Royal.  "I'm pleased with the week – and I've kept my place in the top 16.  I'm delighted overall."

Alex Marshall, the record five times world champion from East Lothian, was taken to the wire by title-holder Greg Harlow, but ultimately drew the shot in the final end of a dramatic sequence of tie-break ends to beat the Ely ace 9-6, 5-7 2-1.

While Marshall had been taken the full distance in his two matches leading to the semis, Harlow had come through the entire tournament without dropping a set

"What a fantastic game – I thought I was never going to win that match," said 43-year-old Marshall.  "I'm shattered!

"It's good to be involved in hard games – it's good preparation for the final.

"I thought I played the better bowls, but often I didn't capitalise on winning positions," added the world number four.

"Being in the final with Paul is fantastic.  But it's hard to play mates and that will add extra pressure.

"He is playing brilliantly - but tomorrow's a new day and it depends which one of us gets to the jack first.  But I'll need to improve my game.

"I now need to practise with my red bowls – I haven't played with them since the Mixed Pairs!" concluded the five-time champion who has never lost in a world final.

Harlow agreed that his opponent had been on form:  "'Tattie' was awesome in the first few ends.  I hung in as much as I could.

"But I didn't think I was as consistent as I have been, and I wasn't as consistent as he was.

"But we played a lot of pressure bowls – which was good.  The last five ends were very eventful – I've never seen so many jacks in the ditch," added the world number two.

"It was a great game – I really enjoyed it.  But the best man won."

RESULTS:    Potters Holidays World Indoor Bowls Championships, Hopton-on-Sea, England

World Singles, semi-finals:
[2] Paul Foster (SCO) bt [3] Mark Royal (ENG) 10-3, 9-2
[4] Alex Marshall, MBE (SCO) bt [1] Greg Harlow (ENG) 9-6, 5-7 2-1

Sunday (23 January) schedule:
2.30pm
World Singles Final
[4] Alex Marshall, MBE (SCO) v [2] Paul Foster (SCO)