Jose Mourinho returns to Italy for the first time since leading Internazionale to victory in Champions League last season as his Real Madrid side chase a fourth straight win in the current campaign and back to back victories against Milan.
Mourinho is looking to win the trophy with a third club, having triumphed with Porto and Inter. He said: "Going back to San Siro is the same as going home. It's a shame it is Milan v Real Madrid instead of against Inter. It would have given me the chance to thank everyone at the stadium for those great two years I had there."
Madrid lead Group G with nine points, five more than Milan, having beaten them 2-0 two weeks ago with Cristiano Ronaldo and Mesut Ozil scoring. "It's important for us to be group leaders after our game in Milan," said defender Ricardo Carvalho. "Our goal is to secure first position as soon as possible and that's why it's important to earn a good result there. We were better at the Bernabeu and Milan's players will want to prove they can defeat us."
Ronaldo has scored 10 times in the last four games, including two in the La Liga win over Hercules on Saturday.
"Cristiano has been scoring many goals for quite some time," Carvalho said. "He looks at the goal constantly and he needs to score to feel comfortable on the pitch."
Zlatan Ibrahimovic has been the main inspiration for Milan so far this season and has three goals in three Champions League matches. "Tomorrow against Real Madrid we have to do everything differently to what we did in Spain," Ibrahimovic said. "At the Bernabeu Real dominated, we were slow and played poorly. Luckily there's another match and if we do things differently from in Madrid we can win and show we are as strong as Real, if not stronger."
Madrid lead La Liga, one point ahead of Barcelona. Milan, meanwhile, are third in the Serie A, five points behind surprise leader Lazio. On Saturday, Milan lost to Juventus 2-1, their second league defeat of the season. "On Saturday our performance against Juventus was good, one our best starts to the season," Milan coach Massimo Allegri said. "The only thing that was missing was the result. When you play these types of games you cannot allow yourself to play poorly. Tomorrow we really have to put the pressure on Madrid."
Ronaldinho missed the game, but hopes to be back. "I feel fine and over the last few days I have done all the work necessary and I want to play my part," he said. "A big game against Real is one you want to play and do your best in.
"In the first leg the two early goals made life extremely difficult for us. Now we have to concentrate on what the coach said so we can get the three points."
Bayern Munich can seal a spot in the second round of the Champions League and set a club record if they can overcome Cluj tonight.
A victory would strengthen the position of coach Louis van Gaal after heavy criticism from club president Uli Hoeness. Bayern's injury list seems to be growing by the day and Van Gaal will have to rely on second-string players to win their fourth straight Group E match. Bayern have never before won its first four group matches. They won the home match against Cluj 3-2 with the help of two own goals by the Romanian club.
"We have to be alert," Bayern defender Philipp Lahm said. "We saw how dangerous they can be if we are not 100 percent concentrated." Striker Mario Gomez said the team was travelling to Cluj to win, but cautioned that, "Cluj is a team that is often underrated."
Hoeness delivered a stinging attack on Van Gaal on live television on Sunday, describing the Dutch coach as someone who is difficult to talk to, who does not accept other people's opinions and who makes poor choices in his team selection.
Bayern said on Monday the club's board and the coach would sit down together soon to discuss and resolve "current differences." Franz Beckenbauer, Bayern's honorary chairman, said Hoeness' intention was most likely to "shake up the place a bit." Van Gaal has not responded publicly to Hoeness' criticism.
The club's chairman, Karl-Heinz Rummenigge, who is mediating between the president and the coach, said Van Gaal was not pleased with Hoeness' remarks. "The important thing, though, is that they stop talking about each other and start talking to each other," Rummenigge said.
In addition to Arjen Robben, Franck Ribéry, Miroslav Klose and captain Mark van Bommel, Bayern have also lost forward Ivica Olic for six months to a knee injury and defender Holger Badstuber will not play in Cluj because of a groin injury. Van Gaal is taking only 15 players to Romania.
Defender Martin Demichelis, midfielder Anatoliy Tymoshchuk and Gomez all scored last week in the 4-2 win over Freiburg in the Bundesliga.
In Basle, Roma will be without injured midfielders David Pizarro and Rodrigo Taddei, but captain Francesco Totti will want to leave his mark since he is suspended for Sunday's Rome derby with Serie A leaders Lazio.