In a classic dual between two Rio 2016 Olympians, Jun took the lead at the final shoot only for the reigning Pan American champion to hit back in the final 200m.

It came after Fernandez had enjoyed a 20 second lead early on in the run before being hauled day by his tenacious rival in an enthralling dual at the Cairo Equestrian Stadium.

Alexander Lifanov of Russia won a distant bronze.

"I am very proud and actually I have no words to describe what happened today," said the 20-year-old Guatemalan winner afterwards.

"This year has been an incredible journey and I have been so close to medals but at the same time so far away. 

"To finish this competition the way I did, I am really happy. 

"After Rio I did not think I was on top form and able to do what I did today.

"What was fundamental for the last part was maintaining my head on the ground and making sure I was concentrating on each shot and in my tactics in running.

"That way I could use the very little energy I had to surpass Jun Woongtae in the last 200m to become the junior world champion."

It meant Jun missed out on emulating the victory secured yesterday by his female compatriot Kim Sunwoo by the narrowest of margins.

"What we saw in this Laser-Run was amazing and seeing three continents represented on the podium shows that our sports is fantastically well developed in all continents, and that makes me very proud," said UIPM President Klaus Schormann afterwards.

"Guatemala is a nation that has organized big competitions in the past including world championships, and their win must represent a big push for more in the future. 

"Charles Fernandez is a great athlete and also an excellent ambassador for our sport, who is now a Member of the UIPM Athletes Committee."

Action is set to conclude tomorrow in the Egyptian captal with the mixed relay competition.