The 22-year-old, who only joined the paid ranks last Monday, capped a sensational effort by signing off with a bogey-free 67 for a 12-under-par 272 total.
Syme broke par in all four rounds at Dom Pedro Victoria and negotiated his last 49 holes without dropping a single shot.
The outstanding week’s work saw him finish ahead of a host of experienced campaigners, including major winners in Padraig Harrington, Paul Lawrie and Danny Willett.
“It was an unbelievable week,” Syme, who was been signed up by Modest! Golf, the management company set up by One Direction band member Niall Horan, after climbing into the world’s top 10 in his final season as an amateur, told .
“I thoroughly enjoyed the experience and I can’t thank the European Tour and Keith Pelley for giving me the opportunity as it was awesome to be out there.”
The Drumoig man parred the first 11 holes in the final round before picking up four birdies in six holes from the 12th.
“The back nine today was fun,” he added. “It could have been a few putter as my putter was a bit cold this afternoon. But I’m not going to grumble about four-under and bogey-free.
“I guess it shows I can compete at this level. It is encouraging going forward as this is just the start of my pro career. Hopefully it is going to kick on from her.
“I will definitely take encouragement from shooting a low number and keeping mistakes off my card. My caddie Tim [Poyser] was a big help today, picking out the right numbers and the flags to go at, which is something you need to learn going forward.”
Syme needed to finish in the top 10 to get into next week’s British Masters at Close House in Northumberland. Unless he gets an invitation for that, his next appearance is likely to be in the Dunhill Links on home soil the week after.
“I’ll have to wait and see where I’m stopping off next, but this was mega-encouraging and it is exciting, that’s for sure,” admitted Syme. “I didn’t know if I was going to get in here after playing in the Walker Cup and I took advantage of that opportunity.”