The Serie A side top Group C, on the same points as Real Madrid, but the French outfit are one point back with two games to play.
Milan's season, less than four months old, has had more twists and turns than a mazy run from Ronaldinho back in his prime at Barcelona.
The 29-year-old, now settled on the left of a front three, blasted in a penalty and produced some exquisite touches in Sunday's 4-3 win over Cagliari.
"For me it's easy to be able to play with intelligent players like Marco Borriello and Alexandre Pato who understand what I can do for them on the pitch," Ronaldinho told reporters.
"Right now playing at the San Siro makes me feel good, here I feel at home, the fans understand I needed their support and this makes me happy."
"It's nice to have beaten Paris before going to Milan, it's good for our confidence," said Argentina defender Gabriel Heinze.
"Milan are a different proposition but I believe we can win there. We have to if we want to qualify," added Heinze who scored the winner against PSG.
Midfielder Fabrice Abriel said the man to watch would be Clarence Seedorf, who set up both Inzaghi's goals in Milan's 2-1 win at Marseille in September.
"Seedorf is their most important player and we'll have to keep an eye on him," said Abriel. "He's the one who gives all the good balls, he's very intelligent and he's real added value for Milan."
