The 21-year-old from Rome made the early running as she notched up three birdies and an eagle on her front nine on her way to a 9 under par total. But it was not as cut and dried as it seemed and the four-time Italian amateur champion had to fend off spirited challenges from Britons Becky Brewerton from Wales, who finished second on 7 under par and Georgina Simpson, who closed in third place one shot further adrift.
Luna was in sublime form all afternoon even with a capricious north-westerly wind threatening to send scores soaring again and had the benefit of compatriot and retired tour veteran Federica Dassu, last years Spanish Open champion, on caddie duties.
Simpson proved the main threat to the Italian for most of the final round as she lobbed in four birdies in the first 10 holes, adding another at the 13th to draw within one shot around this precarious Seve Ballesteros layout.
But the challenge from the 28-year-old from Dewsbury came to an abrupt end with bogies at the 16th and 17th, two of the most demanding holes on the course.
With a three shot lead heading up the 18th, Luna played the tricky final hole perfectly and had a simple two-putt for par which brought on a champagne shower from Stefania Croce, the only other Italian who has won on the LET.
I feel so happy now, added Luna, who has been likened to Sarah Jessica Parker from Sex in the City fame.
Right now, I dont really know what has just happened and I feel a bit confused but Im sure I will realise it all tomorrow.
Federica has been so good to me and shes coaching me full time now. She has really helped me with my confidence on the course and thats why I feel so god when I am playing now. Ive had a couple of top six finishes and I think what Federica has done has helped me get to the next level.
Brewerton, who had been chugging along steadily at 1 under par for the day, overtook Simpson when she birdied both of the final two holes to snatch outright second place for a carbon copy of last years result when she lost narrowly to Elisabeth Esterl, while she was still an amateur.
This time I can get paid for it, said Brewerton, who now has three runners up places in the last season, including last years WPGA Championship of Europe at Royal Porthcawl in her homeland.
It was a good last round and I was happy with my performance, but Diana played very well and hit some awesome shots out there and she deserved to win, so fair-dos, the best player won on the day.