World number one Carlos Alcaraz and Novak Djokovic will aim to set up a tantalising French Open semi-final encounter at Roland Garros on Tuesday.
US Open winner Alcaraz, 20, plays Greek fifth seed Stefanos Tsitsipas in the night match on Court Philippe Chatrier.
Djokovic continues his bid for a record 23rd men's Grand Slam title against Russian 11th seed Karen Khachanov.
In the women's quarter-finals, Belarusian second seed Aryna Sabalenka meets Ukraine's Elina Svitolina.
The winner of that match will play Russian Anastasia Pavlyuchenkova or Czech opponent Karolina Muchova, who are first up on Philippe Chatrier from 10:00 BST.
Elsewhere, Britain's Neal Skupski and Dutch team-mate Wesley Koolhof - the top seeds in the men's doubles - take on Spain's Marcel Granollers and Argentine Horacio Zeballos for a place in the semi-finals.
In the opening day of the wheelchair events, three time champion Alfie Hewett begins against Tom Egberink of the Netherlands.
Doubles partner and two-time runner-up Gordon Reid plays another Dutchman, Mikael Scheffers, while fellow Briton Lucy Shuker faces Dana Mathewson in the women's competition.
Excitement over a potential semi-final showdown between Alcaraz and Djokovic has been building with each passing round since the draw was made at Roland Garros.
The Spaniard, who won his first major at Flushing Meadows in September, arrived in Paris as men's world number one after replacing Djokovic at the top of the rankings last month.
On an 11-match winning run at Grand Slams after injury ruled him out of the Australian Open - won by Djokovic in January - Alcaraz faces his sternest test yet when he plays 2021 runner-up Tsitsipas in his quarter-final (19:15 BST)
Tsitsipas, winless in four previous meetings following his loss in April's Barcelona final, spoke highly of his opponent earlier in the tournament, describing Alcaraz as "a breath of fresh air" and praising his "positive energy".
"Right now he's one of the biggest obstacles and challenges for any player to compete against," Tsitsipas said of Alcaraz.
"It pushes us all to be better. Rivalries like this, they are the toughest thing you can get in our sport."
Walking out for Tuesday's night session on Philippe Chatrier, they will already know whether two-time champion Djokovic awaits in the last four.
The Serbian third seed has won all 12 sets he has played as he seeks to overtake the absent Rafael Nadal by winning a 23rd major this week.
In his record 17th French Open quarter-final, he will look to deny Khachanov a third successive Grand Slam semi-final appearance - and the 36-year-old insists he is not looking beyond that match.
"Khachanov in the quarter-finals. I know what my goal is here," Djokovic said. "I'm trying to stay mentally the course and not look too far [ahead]."
BDST: 1147 HRS, JUNE 06, 2023