Perhaps overwhelmed by the chance to win his maiden title at age 33, Bagnis won just 12 of the first 47 points of the match as 21-year-old Darderi raced to a 6-1, 2-0 lead in just 34 minutes, silencing Argentine fans in the process.
In just the third all-qualifier final since the ATP Tour was established in 1990, Darderi took advantage of an error-laced performance from the World No. 207, who has appeared in 30 ATP Challenger Tour finals but just one tour-level final before Sunday, to run out a 6-1, 6-4 winner.
"I feel really good, I can't believe I have won my first ATP title," Darderi said. "Last week I lost in the [second] round of a Challenger.
“To come through from qualifying to win the title with my family here, my dad and my girlfriend, it's so special. And to make a big move in the rankings."
After the match seemed over early in the second set, Bagnis reclaimed the break and eventually led 4-3 before fatigue appeared to play a factor in him surrendering the decisive break in a six-deuce penultimate game of the match.
Darderi, who had just one tour-level match win to his credit before this week, is projected to surge from No. 136 to No. 76 in Monday’s Pepperstone ATP Rankings. Last week he lost in the second round of the ATP Challenger Tour event in Punta del Este, Uruguay.
Born in Argentina but an Italian national, Darderi is coached by his father, Luciano.