The former Argentina team-mates and rival coaches in La Liga bumped into each other between training sessions at AAMI Park in the city on Thursday and they now meet again at the MCG (8pm local time, 11am UK).
That relationship was naturally one of the topics at Mauricio's pre-match press conference on Thursday.
On Diego Simeone
Mauricio: "Well, if you compare Diego with me, thank you, that’s a big prize. I consider him one of the best managers in the world. He deserves all the credit because it’s always difficult to take a team like Atletico Madrid and play in Champions League finals, win the league in Spain. For me, Diego is one of the best."
Below: Mauricio with Diego
On their relationship as players
Mauricio: "We had a very good relationship when we played in the national team. We have kept this relationship with him and his assistant Ramon Burgos, another great man and great professional. It’s fantastic to see them again."
On taking the game to Atletico
Mauricio: "Our idea is to play in the same way as we did against Juventus, to be brave and to deliver our ideas. We are preparing for our season and it’s always important to deliver the plan. We are in a process and a period where we need to improve and learn."
On Will Miller
Mauricio: "I learned two or three days ago that as a boy he was involved in different movies, a nice surprise. It’s an interesting story. He can be a very good footballer, he’s young, he’s a good boy, a fantastic character and personality."
Below: Mauricio at AAMI Park
On the youngsters
Mauricio: "The most important thing is when they have the opportunity to show their quality, they have to take that opportunity. It’s very good to play this type of game against teams consistently in the Champions League because they can show their quality and personality and we can take a lot of things from these games.
"A good example is Dele Alli. He came from Milton Keynes and after a few months he took a place in the starting 11 and after that, you all know (his story). Young players have a different time to get mature and improve but when they show they have talent, we need to give them the opportunity, and then be careful with them. Look at Marcus Edwards, he’s only 17, he’s a very talented player but we need to help him."