And, in over in Ireland, Paul O’Hara and Christopher Currie both stayed in contention in the PGA Professionals Championship.
Ayrshire ace Stewart finished with a flourish at Montrose Links, holing his second for an eagle at the last as he closed with a seven-under-par 64.
That gave him a 13-under-par 200 total and a share of second spot behind Englishman Chris Lloyd, who claimed the £10,000 top prize by two shots.
Stewart picked up £4,500 for his encouraging effort, his best performance since losing in a play-off on the Alps Tour in 2013.
“I played great over the three days, some of the best golf I’ve ever played, which was nice,” said the Troon Welbeck man. “Today could have been really low as I didn’t hole many putts in all honesty.
“The last hole was obviously a big stroke of luck as I holed a shot from 90 yards from the right rough.”
Stewart won the Scottish Boys in 2008 before adding the Scottish Amateur two years later.
He turned pro after being part of a winning Walker Cup team at Royal Aberdeen in 2011 but this is the first time that he’s really managed to recapture some of his amateur form.
“It was great to be up there contending,” he added after a flawless final-day effort. “It’s been a long time since I’ve felt the buzz of being up there with a chance of winning.
“My game has felt great recently so I’m just happy to be putting scores together and, apart from losing in a play-off on the Alps Tour in Egypt in 2013, this is my best finish as a pro.”
Lloyd, who is attached to The Kendleshire, closed with a 67 as he finally became a winner on the third-tier circuit after coming close to victory several times over the last two seasons.
“I feel like I have been knocking on the door for a little while now,” he admitted. “There is a bit of relief there and plenty of satisfaction.”
Stewart shared second spot with Huddersfield’s Nick Marsh with Sam Prince (Northenden) and Robert Burlison (Enville) both a further shot back in joint-fourth.
Craig Lawrie, Paul’s eldest son, closed with a 68 to finish next best among the home contingent in joint-15th.
Conor O’Neil, who’d shared the lead heading into the final round, slipped to joint-42nd after the Mearns Castle Golf Academy player had to settle for a closing 78.
Meanwhile, O’Hara and Currie are both chasing a £10,000 top prize heading into final round of the PGA Pros Championship at Luttrellstown Castle.
The two Scots are alongside Englishman Christopher McDonnell on one-under-par after a tough scoring day in the 72-hole event.
Caldwell-attached Currie fared best of the trio with a 74, one better than O’Hara and beating McDonnell by three on the day.
Motherwell man O’Hara is bidding to complete a quic double after his wire-to-wire win in the Northern Open at Lossiemouth last week.
Welshman Garry Houston is lurking dangerously, sitting a shot behind the joint-leaders, while others still in the hunt include English trio Phil Archer, Andrew Raitt and Craig Goodfellow.