it will be an England v Scotland final that will bring the World Bowls Tour event to a climax at Dewars Centre in Perth, Scotland, on Saturday.

All four matches were wide open until the very last deliveries – three in tie-breaks and one at five-all after a tied first set.  

Earlier in the day, it was down to a measure of half an inch which separated the two players - and in the last game of the day, unseeded Scot Stewart Anderson clinched the final slot in the semi-finals with a bowl closer to the jack than that of England's world number three Mark Royal by less than an eighth of an inch!

England's Mervyn King secured the first semi-final place after beating Canadian outsider Jamie MacGowan, a qualifier from Vancouver making his World Bowls Tour debut.

Widely fancied to win the title after despatching defending champion and world number one Paul Foster in the previous round, King dropped the first set as MacGowan maintained his giant-killing momentum on the WBT's unique portable rink.

But the 2006 world champion battled back to take the game into a best-of-three-ends tie-break.  And with the Canadian holding shot in the third end, King drew a magnificent last bowl which nudged in between MacGowan's bowl and the jack to claim a 4-8, 7-3, 2-1 victory.

"Credit to him – he played well," said the world No8 from Norfolk.  "I struggled with the pace in the first set – but he didn't give me a chance.  I thought I was on the way out."

When asked what thoughts were going through his mind as he prepared to deliver his all-important last bowl, King replied:  "I thought of the advice given to me by a sports psychologist when we prepared for the Manchester Commonwealth Games - and recalled some of the big bowls I have delivered in previous similar occasions.

"You need to consider the positives rather than the negatives," said the 44-year-old, a silver medallist in Delhi.  "And now I'll be able to recall that bowl!"

King will line up against fellow countryman Robert Paxton, who became the only qualifier to reach the last four after upsetting England captain Andy Thomson, the No10 seed, in a match which went the full distance.

With Thomson having the advantage in the final end of the tie-break, the 32-year-old from Exeter delivered a sensational winning bowl which stopped just half an inch closer to the jack, after a measure.

"I'm exhausted, mentally drained," said Paxton after his 7-4, 3-8, 2-1 win over the 54-year-old.  "It was a really tough game out there.

"Andy is a great player and still has plenty of years left in him."

Paxton first came to prominence on the World Bowls Tour in 2006 when he reached the semi-finals of the world championship.  "I'm now just one win away from a dream place in a final."

Paxton, who has never been selected for England, is competing with a blood clot in his right leg.  "I played most of the game with pins and needles in my foot," explained the world No20, who is due to undergo surgery next week.

Thomson was full of praise of his opponent:  "He played a brilliant bowl in the final tie-break end – and played exceptionally well against Ian Bond in the previous round," said the Londoner.

"But I thought we both played well today," added former world champion Thomson.

Again it took a tie-break to resolve the match between two of the game's giants – England's reigning world champion Greg Harlow and Scotland's David Gourlay, who topped the world rankings for more than six years.

From 4-4 in the first set, Gourlay scored two trebles in a row en-route to taking the set – before Harlow battled back to dominate the second, leading the match into a tie-break.

But, despite Gourlay only having won one end in the previous eight, the 44-year-old Scot played two wonder bowls in response to winning positions by Harlow to clinch a stunning 11-4, 1-9, 2-0 win over the No2 seed.

"In the second set, I just felt totally out of the game as Greg played the best I've ever seen him play," said the Glasgow bowls star.  "I knew I needed to compose myself for the tie-breaks and said to myself 'all I need is two good bowls to win the match' – which is just what I got!"

By his own standards, Gourlay has had a torrid time on the Tour over the past two seasons.  Now ranked 13 in the world, the Scot is celebrating his first ranking event semi-final appearance since 2007.

"Slipping down the rankings is hard.  But winning this title would mean everything – especially as it's in Scotland," added Gourlay.

Harlow, the world No2 from Ely in Cambridgeshire, was philosophical about his defeat:  "It was a great game of bowls and I was happy with the way I played in both sets.

"In tie-break ends, you're only talking about fractions – and nine times out of ten my positions would have been winning positions in those tie-breaks.  David played two shots perfectly – you can't complain.  He's playing well enough to win the title," added the 42-year-old.

Gourlay will pay the game's rising star Stewart Anderson, a 25-year-old from Ayrshire who took the sport by storm in January by reaching the world championship final as a qualifier.

After a tied first set against third seed Mark Royal, the pair went into the final end of the second set with the score standing at five-all.  Anderson's penultimate bowl gave the Scot the shot, but a near perfect response by Royal – with his last delivery – left it unclear who had the winning shot.

With few options open to him, Anderson chose to forego his final bowl, in the hope that his was the winning shot.  After tense moments while the official measure the two gaps, Anderson was indeed judged to be the winner – by less than an eighth of an inch!

"It's the biggest gamble I've ever taken," admitted Anderson, now in the event's semi-finals for the second year in a row.  "I was about 65% certain mine was the winning bowl.

"Getting to a semi, then a final, now a semi in successive events is unbelievable," added the former world junior champion who now lives in Wales.  "When I look at my results, I think that I can compete in the world's top 16."

Quarter-finals:
[8] Mervyn King (ENG) bt [Q] Jamie MacGowan (CAN) 4-8, 7-3, 2-1
[Q] Robert Paxton (ENG) bt [10] Andy Thomson (ENG) 7-4, 3-8, 2-1
[13] David Gourlay (SCO) bt [2] Greg Harlow (ENG) 11-4, 1-9, 2-0
Stewart Anderson (SCO) bt [3] Mark Royal (ENG) 8-8, 6-5

Friday (12 November) schedule:
1.00pm, Semi-Finals
[8] Mervyn King (ENG) v [Q] Robert Paxton (ENG)    
Stewart Anderson (SCO) v [13] David Gourlay (SCO)    

Saturday (13 November) schedule:
2.00pm, Final