Novak Djokovic may have sounded croaky but the four-time Paris Masters champion stayed in the hunt for another triumph in the French capital.
A 7-6 (9-7) 6-1 victory over Great Britain's Kyle Edmund carried the Serbian through to a tough-looking quarter-final against Stefanos Tsitsipas.
Greek youngster Tsitsipas was a 6-3 6-4 winner against Australian Alex de Minaur, while Rafael Nadal dug deep for a gritty 6-4 6-4 win over Stan Wawrinka.
Dominic Thiem and Alexander Zverev were significant casualties, as the fifth and sixth seeds suffered respective defeats to Grigor Dimitrov and Denis Shapovalov.
And there was plenty of French joy, as Jo-Wilfried Tsonga and Gael Monfils thrilled the home crowds with dramatic three-set victories.
Win No. 50 for @RafaelNadal in 2019
— ATP Tour (@atptour) October 31, 2019
Rafa beats Stan Wawrinka 6-4, 6-4 to reach the quarter-finals of the @RolexPMasters for the seventh time!
: @TennisTV | #RolexParisMasters pic.twitter.com/a67eAhc7cr
Djokovic eyes revenge
Djokovic lost to Tsitsipas in the quarter-finals of the Shanghai Masters in October but will fancy his chances of avenging that loss on Friday.
Despite his voice sounding far from healthy, Djokovic is feeling better after battling illness this week, and he is positive about the state of his game.
"The second set was the best set I've played so far in the tournament," Djokovic said, according to the ATP website. "Finished off with a winner, finished off with amazing return game. So, of course, the sensation is very positive. And I'm convinced that I'm headed in the right direction so that tomorrow will be even better."
The 32-year-old hopes to end the year at number one in the world rankings for the sixth time, even though Nadal is certain to be in pole position heading into the ATP Finals in London.
Tsonga next for Nadal
Nadal was not at his best against Wawrinka, yet he still extended his dominance over the Swiss three-time grand slam winner with a 19th win in their 22nd meeting.
He took two of the three break points he engineered to stay in the hunt for a first Paris Masters title. Given his immense success elsewhere - his 35 Masters 1000 titles is a record and he has landed 12 French Open titles - Nadal's limited success in Paris is a shortcoming he will be eager to address.
He should have enough for Tsonga on Friday, but the veteran Frenchman has come out punching this week and is beginning to look like the player who was a top-10 fixture for so long.
Tsonga landed a 2-6 6-4 7-6 (8-6) victory over Germany's Jan-Lennard Struff and said: "When you play the best, it's always beneficial and it's not important whether you win or lose.
"When you play Rafa in the first round, it's a problem. If you play Rafa in the quarter-finals, it's normal. Of course, it's better for me to meet Rafa in quarter-finals after having played a few matches rather than during the first round."
Is Monfils marching to the #NittoATPFinals?
— ATP Tour (@atptour) October 31, 2019
@Gael_Monfils defeats Albot to reach the @RolexPMasters final eight & is just ONE MATCH AWAY from making London!
: @TennisTV pic.twitter.com/cpLkPgZilE
Monfils keeps ATP Finals hopes alive
There is one place to fill at the season-ending ATP Finals, and Monfils is desperate to sustain his run this week to stay in contention.
After a 4-6 6-4 6-1 win against Romanian Radu Albot, the 33-year-old Parisian is on the brink but still not quite there and must see off Shapovalov to earn his ticket to London ahead of Matteo Berrettini.
Given Shapovalov's 6-2 5-7 6-2 win against Alexander Zverev, that could be a tall order for Monfils, whose French compatriot Jeremy Chardy could not boost the home contingent in the final eight, going down 6-7 (4-7) 6-4 7-6 (8-6) in a nail-biting thriller against Chilean Cristian Garin.
Despite the defeat, Zverev is certain to be involved in the English capital after sealing his spot on Wednesday.