The Turnhouse player bridged a 27-year gap when he earned a Scotland recall for the Home Internationals in 2016 and is now closing in on another notable feat. On the second day of the match-play phase at the Perthshire venue, he came from three down to beat Kyle Godsman (Moray) 2&1 in the third round before then defeating Australia-based Connor Mckinney (Joondalup) with a birdie at the first extra hole.
McIntosh, a former professional who is preparing for another crack at the paid ranks once he turns 50, now meets Stephen Roger in the semi-finals after the Peebles player birdied the last to claim a shock win over title favourite Euan Walker (Barassie).
The other last-four clash is between Lanark’s Andrew Thomson, who defeated East of Scotland Open champion Matt Clark (Kilmacolm) on the last, and Jamie Stewart (Old Ranfurly).
Bidding to add this title to his Scottish Under-16s Championship success, Stewart made seven birdies, including four in a row to close out the match, as he progressed with a 5&4 win over Jim Johnston (Ayr Belleisle).
Elsewhere, overnight leader Colin Montgomerie slipped four shots off the lead following a level-par 72 in the second round of the Staysure PGA Seniors Championship at London Golf Club in Sevenoaks while Open Silver Medal winner Sam Locke carded a 68 on day two in the Swedish Challenge to make the cut on his professional debut.
In Akron, England’s Tommy Fleetwood and Ian Poulter claimed a share of the clubhouse lead as low scoring continued at the WGC-Bridgestone Invitational.
Overnight leader Poulter added a second round of 67 to his opening 62 at Firestone Country Club for a halfway total of 11 under par which was matched by compatriot Fleetwood and world No 3 Justin Thomas.
Fleetwood fired seven birdies in a flawless 63, while Thomas birdied five of his last eight holes in a 64.