Became the third Italian winner of the European Amateur Championship in eight years at El Saler in Spain in June.
Ranked 149th in the amateur game at the time, the Rome golfer opened with a dazzling eight under par 64 containing seven birdies and an eagle before losing top spot to compatriot Pietro Bovari on day two.
A second successive 73, however, was good enough in the windy conditions to take him back out in front and after finding himself in a five-way tie for the lead at one point on the final day he held his nerve and in the end finished one ahead of Dane Rasmus Neergaard-Petersen.
"I've been waiting to win a trophy like this all of my life,” he said. “I don't have the words to describe my feelings right now. I woke up and told myself ‘Filippo, enjoy the day. You are living for competition and to feel under pressure. Have fun and see what happens - and this is what happened".
Rory McIlroy and Sergio Garcia are previous winners of the title. Celli was runner-up in last year’s Italian stroke play championship and in May a quarter-finalist at the Italian match play.