Daniil Medvedev and Stefanos Tsitsipas will reignite their often ill-tempered rivalry when they meet in the French Open quarter-finals on Tuesday.
Greek fifth seed Tsitsipas has previously referred to Medvedev's game as "boring" and remarked the two "would not go for dinner together".
And Russia's Medvedev suggested this week that relations had not improved.
"It seems to me that we respect each other as players but not too much on a personal level," the second seed said.
Medvedev leads their head-to-head 6-1 and thrashed Tsitsipas in straight sets when the two met in the Australian Open semi-finals in January.
His only loss to the Greek came at the ATP Tour Finals in 2019 - a tournament which Tsitsipas went on to win.
The two clashed in their first meeting at the Miami Open in 2018, with the chair umpire forced to step in when the two began arguing at the end of the match.
Germany's Alexander Zverev, who had his breakthrough alongside Tsitsipas and Medvedev, has described their relationship as "weird", with the two cutting different figures on court.
Medvedev has been known for his volatile but entertaining antics - he memorably won the crowd over by the end of the US Open in 2019 - and he has gone on to reach two Grand Slam finals.
This is the furthest he has been at Roland Garros after falling in the first round in his previous four appearances.
Tsitsipas' best result here was reaching the last four last year and he is generally more comfortable on clay than Medvedev.
"Our chemistry definitely isn't the best that you can find on the tour," Tsitsipas said of Medvedev two years ago.
"But he tricks you. He plays the game really smart."
Medvedev, meanwhile, has described Tsitsipas as his "greatest rival".
The pair are scheduled to play at 20:00 BST, having been handed the night session billing but there will be no fans in the stadium as Paris is still under a curfew as part of coronavirus restrictions.
Germany's Zverev will play Alejandro Davidovich Fokina of Spain in Tuesday's other men's quarter-final earlier in the day.
Who plays who in the women's draw?
There is guaranteed to be a player appearing in their maiden Grand Slam semi-final in the women's draw.
Russia's Anastasia Pavlyuchenkova is the most experienced of the quartet who are playing on Tuesday, having reached the fourth round at the French Open in 2011.
She beat two-time Slam champion Victoria Azarenka and in-form third seed Aryna Sabalenka in the previous rounds.
She will face her doubles partner Elena Rybakina, who ousted Serena Williams, for a place in the semi-finals.
At 22 in the world, the Kazakh is the highest-ranked player in this side of the draw.
Spain's former Roland Garros junior champion Paula Badosa, who has 17 wins on clay this season, will play unseeded Tamara Zidansek in the other quarter-final.
Slovenian Zidansek, ranked 85 in the world, had previously never gone past the first round at Roland Garros.