Argentinian Diego Schwartzman moved within one win of reaching the ATP Tour Finals for the first time thanks to a third-round thrashing of Alejandro Davidovich Fokina at the Paris Masters on Thursday.
The sixth seed raced to a 6-1, 6-1 victory in only an hour and will face third seed Daniil Medvedev in the quarter-finals on Friday after the Russian's 5-7, 6-2, 6-2 win over Australia's Alex de Minaur.
Schwartzman will qualify for the Tour Finals if he wins that match or if Pablo Carreno Busta does not take the title.
"Tomorrow (Friday) is going to be a different match and it will be tough because I want to be in London," said Schwartzman. "I need to do everything in my hands."
The season-ending event, being played in London for the last time before moving to Turin, gets underway on November 15.
Davidovich Fokina beat former Bercy champion Karen Khachanov in the first round, but was no match for Schwartzman.
The 28-year-old broke five times and saved the four break points he faced, which all came in the opening game of the match.
Medvedev battled back from a set down to see off US Open quarter-finalist De Minaur and reach the last eight for the first time.
All seven of his ATP Titles have come on hard courts, with three of those also indoors.
"When you win such matches, especially in the way I did it, playing really good, sometimes (it) gives you extra confidence," said the world number five. "Hopefully that's the case."
The winner of Schwartzman and Medvedev could face Milos Raonic in the semis, after the Canadian saw off American world number 91 Marcos Giron 7-6 (7/1), 6-1.
Former Wimbledon runner-up Raonic will play French youngster Ugo Humbert in the quarters.
The 22-year-old, who won his last tournament in Antwerp, made it eight straight victories by edging out Marin Cilic 6-3, 6-7 (4/7), 6-3.
In-form Spaniard Carreno Busta kept his Tour Finals hopes alive with a 7-5, 6-2 win over Slovakia's Norbert Gombos.
He will next face the victor of the third-round tie between Rafael Nadal, fresh from his 1,000th Tour win, and Australian Jordan Thompson, which takes place later on Thursday.