The Italian started the final day at Education City Golf Club six shots off the lead but had spent the previous evening watching Thomas fire a brilliant eight under par 64 at The Players Championship on the US PGA Tour.
He set that as his own target and while he fell two short in his round, it looked like he had done enough to earn a play-off at seven under for the week, with rival Antoine Rozner 60 feet from the hole on the last in two.
But the Frenchman holed an incredible double breaker over the ridge to snatch the title and deny Migliozzi a shot at European Tour win number three.
"I was watching Justin Thomas, who shot eight under par, at The Players," he said. "I said to my caddie this morning on the range ‘let’s try and shoot eight under par and we’ll see what happens’.
"Four under par on the front nine and two under on the back nine, it wasn’t easy.
"I’m really happy with my game today. I played solid from tee to green and also on the putting green it was better. I was able to read the greens better than yesterday.
"Yesterday it was very tough with all the wind and that was difficult. Today I played really solid and I’m really happy.
"I knew that if I had a really good round I could move up the leaderboard. I did a good job on the course with my caddie."