The 17-year-old edged out Ayr Belleisle’s Jack Broun after they were tied on level par 216 after three rounds over the Lansdowne course. Taylor Kerr (Sanquhar) was third on 217.
The victory lifted Dalziel, the 2017 Scottish Boys champion, to the top of the Scottish Order of Merit.
The dramatic finale was watched by Bradley Neil, hard on the heels of flying in from the Far East after missing the cut at the “Volvo China Masters,” and 2014 Ryder Cup winner Stephen Gallacher, whose son Jack finished in fourth spot after a count back in the U18 event.
The tournament was held in honour of long-time servant to Scottish Golf and R&A selector Barrie Douglas, who passed away last year after taking ill while captaining the Scottish boys at the European Team Championships in Spain.
Local player Gregor Graham (14) also required a play-off hole and a birdie putt to capture the U16 title against Nairn’s Calum Scott after they also finished tied on 216. Another Blairgowrie competitor, Cormac Sharpe, was third on 219.
Airdrie GC member Dalziel said: “This is one of my best victories and it was my first ever play-off.
“It was great to be part of an event in memory of Barrie and to go down as the first winner.”
U16 champion Gregor was cheered on by fellow Blairgowrie member and close family friend Neil.
Graham said: “It’s my best ever victory and doing it at my home club with the family supporting me makes it even better.
“Bradley has helped me with my game since I was six-years-old and it was great he was also there to see my win.”
Tour star Gallacher, who is looking forward to his own Foundation’s event at Cardrona in June, welcomed a new world ranking points tournament on the Scottish junior calendar.
He said: “The more competitive tournaments like this with ranking points at stake, with national selectors looking on, the more chance the kids have to perform and gain experience.
“The organisation was very professional and the golf course is wonderful. I walked it three times watching Jack and caught a few holes towards the end of his Sunday round.
“It’s been a credit to Barrie and his memory. He was lovely man and it was nice to support the tournament.”
Neil added: “I flew in from China and wanted to be part of the event because Barrie did so much for my career. It’s great to see the tournament being so successful.
“The feedback from players and parents has been fantastic and this is just the first year.
“It seems like every junior in Scotland wants to be here and it can only go from strength to strength.”
Scottish national boys coach Spencer Henderson said: “We have been bowled over by the reaction from players and parents. We are already working on dates for next year. The event is here to stay.
“Blairgowrie Golf Club staff and members rolled out the welcome mat and an army of volunteers ensured the tournament passed off without a hitch. Even the weather played ball on Sunday for the final round.
“I know Barrie would have wondered what all the fuss was about, holding an event like this in his name. But I think he would have been quietly chuffed because it can only help with the development of young golfers in Scotland and he was passionate about that.”
Support sponsors included Carbon Financial, GS Brown Construction, A&J Stephen, The Blue Group, T’Go, GS Group, McLeod Glaziers, Dental Technique, Club 300, Barclays Bank, Decorum Decor and the Gibson family.