For his first semi-final on the circuit, Lestienne will face Croatian Marin Cilic (16th in the world), who benefited from the withdrawal of Briton Liam Broady (174th).
The 30-year-old had dismissed Finland's Emil Ruusuvuori (54th) in two sets (6-4, 6-2) in the previous round.
A professional for ten years, Lestienne played his first quarter-final in an ATP 250 tournament last week in San Diego.
He is guaranteed to play at the Australian Open early next year for his first foray into the main draw of a Grand Slam tournament.
Lestienne is the last Frenchman in the running since his fellow tricolor Arthur Rinderknech (58th) was sharply beaten by the Russian Roman Safiullin (6-4.6-1) in 1h09 of play.
© 2022 AFP