He beat experienced Australians Terry Gale and Noel Ratcliffe with a birdie three at the fifth visit to the 18th green after the trio had tied on eight under par 208. It was his first significant tournament win.
McDermott had already added drama to the final afternoon by covering the last six holes in six under par, including a hole in one at the 201-years 13th.
His back nine of just 30 strokes also featured birdies at the 12th, 14th, 16th and 17th. His closing six under par 66 matched the seniors course record set by Spaniard Antonio Garrido the previous day.
With Gale, the 1996 PGA Seniors champion, already in the clubhouse on 208 after a 69, the pair turned their attention to overnight leader Ratcliffe in the final match.
When the big Australian drove in to the 18th fairway at nine under par it looked all over. But he left his 100-yard pitch 20 yards short of the green and was lacking in distance again with his chip before missing the putt and a chance of outright victory.
Worse was to follow when Ratcliffe hooked his drive at the first hole of the play-off over the 353-yard 18th. He bogeyed the hole again and left Gale and McDermott to play out with par figures. They repeated the score at the same hole three more times before McDermott finally slotted his ten foot birdie putt.
Gale had a chance to match it from nine feet but missed and had to be content with a share of second with his fellow countryman.
McDermott, who collected the £14,445 top prize said: “I don’t know just how I made the play-off in the first place. It’s fantastic. But my golf is getting better all the time.”
This was not his first dramatic experience. He only qualified for a full European Seniors Tour card by knocking a five wood straight into the final par five hole for an albatross two at last year’s Tour school in Hardelot.
Yesterday he used a three wood into the wind for his hole in one at the 13th, the 14th ace of his career.
But while a comparative unknown was producing the fireworks more illustrious names were having less excitement. Brian Barnes and Tony Jacklin were both taking a break from competing on the US Seniors Tour but, although Jacklin opened with an encouraging four under par 68 to share the first day lead, neither seriously threatened over the final two rounds.
Barnes improved every day, his final 69 putting him on 214 with a share to 8th place. But Jacklin moved in the other direction with 73 and 75 to drop back to level par.
American senior rookie Bob Lendzion whose victory in the Beko Classic in Turkey the previous week put him on top of the Money list, seemed in good shape for another winners cheque after 17 holes of the second round.
He was leading the tournament at eight under before driving out of bounds and running up a triple bogey seven, a set back from which he failed to recover, carding a last round 75 for 214.
Irish legend Christy O’Connor, making a rare competitive appearance, beat his 73 years with a level 72 in the second round before closing with a 75 for 223.
Winner of the Lynx Super Seniors Prize
Doug Dalziel
