Nagal got the better of Cerundolo 7-6 (2), 7-5 to set up a semi-final clash with Argentinian Juan Ficovich.
Earlier this week, Nagal beat Facundo Bagnis of Argentina 6-4, 6-2 in the final at the Buenos Aires ATP Challenger clay event to claim his second Challenger title and move up by 26 spots to 135 in the rankings issued by Association of Tennis Professionals (ATP).
He had won his maiden title in 2017 at the Bengaluru Challenger event.
Earlier, this year, Nagal rose to fame after he went down fighting 6-4, 1-6, 2-6, 4-6 to Swiss legend Roger Federer in the US Open in August. He became the fourth Indian to win a set in the main draw of a Grand Slam in the last 20 years by virtue of taking a set off Federer.