Madrid has already clinched winning Group G and is joined in the knockout stages by second-place AC Milan.
Auxerre trails Ajax by one point for third place, which offers direct passage into the Europa League.
Auxerre will advance only if Ajax loses and it manages at least a draw at Santiago Bernabeu Stadium, where Madrid has won all 10 games played over all competitions.
Mourinho is serving a one-game ban for deliberately instructing Xabi Alonso and Sergio Ramos to incur red cards in a victory at Ajax, a sanction that Auxerre coach Jean Fernandez didn't agree with.
"He's not the only coach who has acted in this way. The punishment seems exaggerated to me," Fernandez said Tuesday. "If it's done for Mourinho it should be extended to all coaches. I would have done the same thing." As well as the suspended Alonso and Ramos, Madrid is without injured players Gonzalo Higuain, Angel Di Maria and Sami Khedira. Goalkeeper Iker Casillas is being rested.
Cristiano Ronaldo _ who leads Madrid with three goals _ is within a booking of being banned for the Spanish club's first knockout-stage game, but caretaker coach Aitor Karanka said that might not matter Wednesday.
"Cristiano has to be half dead to not go out and play," Aranka said. "He always wants to play, including when he has injuries that would keep others from even going on the field." A fifth victory would allow Madrid to close unbeaten in its best-ever finish in the current Champions League group format.
"In Amsterdam, some of those who aren't regulars played and things worked out very well," Aranka said of the 4-0 win over Ajax. "With such a busy calendar, there are enough games for everybody. There are no insignificant games _ we want to win so we can go into the next round with a record number of points." Auxerre lands in the Spanish capital without a victory in its last four games in all competitions.
The French club will count on the return of Jean-Pascal Mignot from a two-game ban, but midfielder Delvin Ndinga (quadricep) and midfielder Cedric Hengbart (hamstring) join the long-term injury absentees.
"Tomorrow we'll try to score points but it's still going to be difficult," Fernandez said.
Like Madrid, Milan is likely to rest most of its regulars at Giuseppe Meazza Stadium with its place in the last 16 assured.
Veteran defender Alessandro Nesta is likely to sit out while Milan coach Massimiliano Allegri is unlikely to field Gennaro Gattuso, Kevin-Prince Boateng, Gianluca Zambrotta and Luca Antonini as they are one booking away from missing a match in the knockout phase.
The Italian leader is on a six-match unbeaten run in Serie A to hold a three-point lead over Lazio.
Saturday's 3-0 win over Brescia showed the attack was holding despite the absences of Alexandre Pato _ who is missing as he seeks consultation on another muscle injury _ and Filippo Inzaghi, who is out for the season following knee surgery.
Ronaldinho has also appeared in form lately, but has largely been relegated to a bench role.
"We've got the right spirit," said defender Mario Yepes.
"But the season still has a long way to go and we want to do well in every competition _ Serie A, Champions League and the Italian Cup." Ajax, meanwhile, can guarantee its European League place with a victory, although these have not been forthcoming of late, with coach Martin Jol quitting the team abruptly.
Former Netherlands defender Frank de Boer takes over for Jol with Ajax winning only twice in its last eight games and sitting fourth in the Eredivisie in a matchup of teams that have won Europe's top prize a combined 11 times.
Uruguay striker Luis Suarez is available for Ajax despite a seven-match domestic league ban for biting PSV midfielder Otman Bakkal.