Tsitsipas keeps ATP Finals hopes alive with gritty win in Paris
The 26-year-old Greek, ranked 11th in the world, is in contention for a place in the Turin showpiece, which runs from November 10th-17th, although there are other better-placed rivals still involved in Paris.
He, Alex de Minaur of Australia and veteran Bulgarian Grigor Dimitrov all still aspire to take one of the three places still up for grabs.
Novak Djokovic (6th), Andrey Rublev (7th), Casper Ruud (8th) currently occupy the final three spots but are either not competing in Paris or have already been knocked out.
"Starting the second set, I felt like a bull," said Tsitsipas who likely needs a run to the Paris final to stay in contention for Turin.
"I was ready to fight until my last breath on the court."
For a time it seemed Tsitsipas would also be leaving Paris prematurely as Cerundolo swept through the first set tie-break.
However, Tsitsipas, who beat Cerundolo on their only previous meeting in Basel earlier this month, broke the Argentinian in the third game of the second set.
He held onto the break and levelled the match by taking the set 6-4 on his fourth set point.
Tsitsipas had the upper hand in the decider, easing through from 1-1 and cruised through to win it 6-2.
He will face either world number three Alexander Zverev or France's Arthur Fils for a place in the semi-finals.
Jordan Thompson, the 28th-ranked Australian, made the quarter-finals of a Masters event for the first time by beating Fils's compatriot Adrian Mannarino 7-5, 7-6(5).
Thompson, 30, will next face either Carlos Alcaraz or another Frenchman Ugo Humbert.
