Trungelliti, who came through the tournament's qualifiers, upset Italy's defending champion Luciano Darderi 6-4, 7-6(2) to break the previous record held by Victor Estrella Burgos of the Dominican Republic, who reached his first final aged 34 years in 2015.
Darderi, ranked 19 in the world, was only six years old when Trungelliti turned pro in 2008. With the victory, Trungelliti secured just his second career top-20 win.
"Of course, I believed it, that's one of the reasons that I'm here. Otherwise it wouldn't be possible," Trungelliti said in the on-court interview.
"I've worked a lot, me and my team and also my wife, my kid. We all believed in breaking the record basically and that’s exactly what we have done now."
The milestone caps a remarkable journey for Trungelliti, who made his first ATP Tour semi-final in 2018 in Umag, Croatia - 402 weeks ago.
Having entered the tournament ranked 117 in the world, Trungelliti's breakthrough week has already guaranteed he will crack the top 100 for the first time. He is currently ranked number 75 in the live rankings.
"It's been happening the whole week, leaving the court with a victory," added Trungelliti, who has dropped only one set at the tournament. "So hopefully (there) is one more to go."
He will face Rafael Jodar on Sunday after the Spaniard prevented an all-Argentine final with a 6-2, 6-1 victory over Camilo Ugo Carabelli.