For Jose Mourinho, it's a return to Stamford Bridge to visit the site of his two Premier League wins. His spell in west London ended in acrimony, and while he's lauded by many fans as a hero, there's bound to be an edge about the occasion.
Carlo Ancelotti, meanwhile, will make a similar pilgrimage to San Siro, site of his AC Milan career. To face Inter, then, is particularly special.
But what have the coaches in question had to say about each other, and about their opponents? Below we look back over some of their choice quotes...
Jose Mourinho (Inter)
Carlo Ancelotti (Chelsea)
"Do I miss Ancelotti? No. I am never friends with my colleagues. There are those who are nice, and others who are not," Mourinho comments on his first Milan derby without Ancelotti on the other bench, August 2009.
"I always make my own formation. It's never told to me. There are many coaches who have won the Champions League a few times. Carlo is one of them. He is also the only won to have lost a final after being 3-0 up," February 2009 in response to Ancelotti's comment on Inter's Champions League exit.
"Maybe he could do well at Chelsea because he is a great coach and they are a great club. He has the time and resources to do well there," Mourinho's ironic side after Ancelotti joined the Blues, June 2009.
"Ancelotti is the only one who thinks Adriano's goal was a handball. Does he think we are all dumb? Perhaps he is [dumb] when he fails to speak about Ronaldinho's offside goal in the first derby when they won," Mourinho defends Adriano's handball derby winner, February 2009.
"Our situation is different to Milan as they no longer have any ambition and we are in March. Ancelotti is 11 points behind us in the league and will end the season with nothing (Zeru Titoli)." April 2009 as the Scudetto race drew towards a conclusion.
|"I have friends outside of football. Mourinho is just a colleague who I respect. Friends? He is not my friend. Maybe in future when we are at the end of our careers." Ancelotti reminds Mourinho about their special relationship, August 2009.|
“If Mourinho is Jesus, then I am certainly not one of his apostles," Ancelotti reveals his philosophical side, October 2009.
"Mourinho? I am not fascinated by his personality when he communicates. Sometimes he says useless things. I focus on work. But if he invites me to Appiano Gentile to see one of his sessions then I will go, regardless of their Champions League exit against Manchester United," the Italian scoffs at Inter's Champions League exit, March 2009.
"Looking at the formations of Inter and Lazio, the Nerazzurri's loss seems incredible," August 2009, 'Carletto' takes a swipe at Inter's Supercoppa Italiana loss to Lazio.
"I could never coach Inter. For me it would be like going backwards and against my own history. I am happy at the worlds most successful club." February 2009 ahead of the Milan derby.