PARIS: The first four Champions League groups conclude on Tuesday with a host of major clubs including Real Madrid, AC Milan, Juventus and Bayern Munich still unsure of a place in the knockout phase.

Real are practically assured of qualification and can afford to lose their Group C clash at Marseille on Tuesday by three goals, while Milan will progress from the same group with victory at FC Zurich.

Brazilian playmaker Kaka has been ruled out for Real due to a groin injury but Cristiano Ronaldo is expected to start despite being sent off in his side's 4-2 La Liga win over Almeria on Saturday.

Karim Benzema was on target against Almeria, converting a rebound in the 83rd minute to put his side 3-2 up after Ronaldo had seen a penalty saved, and the former Lyon striker is likely to receive a hostile reception from the Marseille fans.

"It's always a pleasure to return to France. We expect the match in Marseille to be tough," he said.

German giants Bayern Munich travel to Juventus in Group A knowing that only a win will prolong their Champions League campaign.

Juve lost 2-0 at Bordeaux in their last match in the competition, handing the French champions top spot in the group, but they warmed up for the visit of Bayern with a rousing 2-1 win at home to Serie A leaders Inter and need just a draw against Bayern to join Bordeaux in the last 16.

"This can be very useful going into the Bayern game if we are smart, humble, focused and realise we can play with this aggression against everyone," said Juventus's veteran forward Alessandro Del Piero after the win over Inter.

"If we forget that, then we run the same old risks."

Bayern will still be without tendinitis victim Franck Ribery for the trip to Turin but Dutch winger Arjen Robben and Belgian centre-back Daniel van Buyten have both overcome injuries to be included in the squad.

The four-time European champions endured a poor start to the season but their 2-1 win at home to Borussia Moenchengladbach on Friday extended their unbeaten return in the league to eight matches and took them up to third in the Bundesliga standings.

"We have three games left until the winter break," said goalkeeper Hans-Joerg Butt. "We have to win them all, and we can win them all."

Elsewhere on Tuesday, Wolfsburg can join Manchester United in the knockout round if their result at home to the English champions in Group B is better than what CSKA Moscow achieve at Besiktas.

United will tie up top spot, and subsequently a favourable draw in the last 16, with a draw at Wolfsburg but coach Sir Alex Ferguson will be forced to field a makeshift defence due to a mounting injury crisis at the club.

"I don't know where I'm going to get a back four for Tuesday," Ferguson said after his side ended the 4-0 Premier League win at West Ham on Saturday with midfielders Darren Fletcher, Michael Carrick and Ryan Giggs playing in defence.

"The injuries in defence are becoming a bit of a headache to us. Michael Carrick stepped in and did very well."

Chelsea and Porto are already sure of a place in the next round, Chelsea as winners of Group D, but Atletico Madrid will seal a consolation berth in the Europa League if APOEL Nicosia fail to win at Chelsea.

Defending champions Barcelona travel to Dynamo Kiev in Group F on Wednesday and can afford to lose by any two-goal scoreline apart from 2-0 and still go through due to their head-to-head record, while in the same group Inter Milan face a winner-takes-all home meeting with Russian champions Rubin Kazan.