The six-year-old from Five Oak Green was one shot of the lead after the opening nine-hole round of the two-day competition, scoring an eight-over-par 44.
The second day dawned cold and windy but Alexander went round in five-over 41 to record the best score over the two rounds, winning by six shots.
His father Paul said: “The Disneyland Paris course was an extremely challenging one, with lots of bunkers and water everywhere. Alexander seems to thrive on pressure. It appears to bring the best out in him.
“As parents we are delighted with his success and so very proud,” he added. “It’s taken us a bit by surprise and it’s a shock, so we are still taking the enormity of it in. We now have to work out the logistics of getting him to the World Championships.”
The prestigious event is being held at Pinehurst in North Carolina, where more than 1,500 young golfers will assemble from over 50 different countries on August 1-3.
“We weren’t quite expecting this and now feel like we’ve walked into a world completely out of our comfort zone,” said Paul.
“This is all a million away from just taking him down the driving range for something to do, which is how this all started.”
Alexander, who attends Capel Primary School, took up the sport when his mother Claire returned to work after maternity leave.
“Whilst he was in daddy day care I didn’t know what to do with him, and I didn’t fancy being the only dad at mum-and-baby groups,” said Paul. “So I used to take him with me to the driving range.”
Dunmall Snr was a member at Lamberhurst Golf Club but has now given up playing to be a caddie for Alexander. “He first started hitting a club when he was two, and began lessons at four years old.
“I try to give him advice but, being his dad, he doesn’t always listen to me.”
Alexander has recently joined Kings Hill as junior member and spends his time at Tonbridge Driving Range, where he is coached by Zachary Marsh of the Mark Janes Golf Academy.
He stands out from his peers because of his strength, which allows him to drive the ball a long way – his personal best is 170 yards.
“He is very strong, and very broad in his build,” said Paul. “He therefore has an awful lot of power for his age compared to the other children on the circuit.
“It’s not uncommon for him to be able to get the ball from the tee to the green in one, depending on the yardage.
“He is also very driven and competitive,” he added. “He loves all sports but he has a talent for hand-eye coordination and he also plays tennis and cricket.”
The Dunmalls would like to obtain sponsorship to help Alexander’s progress. For more information please contact firstname.lastname@example.org