AC Milan and Real Madrid will swap roles on Tuesday when they meet again in the Champions League while Inter Milan and Atletico Madrid are among 10 sides still seeking their first wins of the group phase.

Barcelona, beaten 1-2 at home by debutants Rubin Kazan last time out, visit the same team on Wednesday knowing that another defeat would put them out of the top two in Group F. The group stage's fourth round of matches could also be crucial for the fortunes of former champions Bayern Munich and Liverpool, currently out of the top-two places in their groups.

Real playmaker Kaka returns to the San Siro stadium for the first time as the Spaniards visit his old club hoping to avenge their 2-3 defeat at the Bernabeu. That result prompted a dramatic turnaround in the fortunes of the two sides. AC Milan's rookie Brazilian coach Leonardo, who went into the game under severe pressure, is now sitting pretty after an unbeaten seven-match run while opposite number Manuel Pellegrini is feeling the heat.

"Real is a game which you especially prepare for. We hope to maintain our high level of play," Leonardo said.

Pellegrini's position was questioned after Real's embarrassing 0-4 defeat by third-tier Alcorcon in the King's Cup made it three games without a win. A defeat on Tuesday could see another storm brewing for Pellegrini, who will again be without injured Cristiano Ronaldo.

Milan and Real top Group C with six points, three ahead of Olympique Marseille and FC Zurich who meet in France.

Crisis-hit Atletico, on just one point in Group D, are unlikely to improve their record when they host in-form Chelsea on Tuesday. Chelsea beat the Spanish side 4-0 two weeks ago and have scored 13 goals without reply in three domestic games since.

Carlo Ancelotti's team have nine points, one of four teams with 100 per cent records along with Manchester United, Lyon and Sevilla.

Manchester United face CSKA Moscow in the Champions League at Old Trafford on Tuesday with Sir Alex Ferguson warning the hosts they have not qualified for the latter stages just yet. Ferguson's side have won all three of their Champions League matches so far, including this corresponding fixture in Russia, and stand on the cusp of reaching the knock-out stages.