Sean Marc already shared the Broomieknowe course record but now holds it outright.
It follows the former Lothians champion carding an eight-under-par 62 at the Bonnyrigg course.
“One of those nights,” said Marc of firing 11 birdies and taking just 22 putts, including a three-putt at the 13th.
His effort lowered the record, shared with clubmate Kevin Hastings and Stuart McLaren of Bruntsfield Links, by two shots.
• Young guns
Connor Graham and Kiron Gribble both recorded wire-to-wire wins in the Stephen Gallacher Foundation event for rising young stars in the Lothians.
Graham is the foundation’s new under-12 champion after claiming that title by five shots with an impressive front-running display at Gogarburn. His 139 total included a two-under 41 in the second round.
Held at the same venue, Gribble also led from start to finish to win by eight shots in the under-10s event. He was a model of consistency over the three days with rounds of 54-54-53 for a total of 161.
• Leitch wins Merchants title
Mike Leitch beat three former champions en route to winning the Merchants of Edinburgh title for the first time.
Adam George was the first past winner to fall to Leitch in the quarter-finals and he then beat Dave Sibbald in the last four.
That set up a title decider with the holder, Andrew Helm, and Leitch produced some brilliant golf in high winds and rain to win five holes on the bounce from the 12th in the afternoon round to triumph 3&2.
• Ranking points leaders
Bathgate’s Fiona Watt and Norman Horsburgh (The Musselburgh) are out in front in this season’s Lothians MyGolfRanking points tables.
Watt, with 1,125 points, leads from Gill Hunt (Turnhouse) on 1,097 while Horsburgh, with 1,283 points, sits ahead of Craig Gray (Glencorse) on 1,235 points.
On the club front, Dundas Parks are the ladies’ leaders on 941, with The Musselburgh just three ahead of Linlithgow in the men’s standings with 913.