Match ends, Real Madrid 2, Viktoria Plzen 1.
Real Madrid beat Group G rivals Viktoria Plzen, but it was another unconvincing display by the European champions, whose coach Julen Lopetegui reportedly faces losing his job.
The Spanish giants came into the game on the back of four defeats in five games in all competitions.
Karim Benzema's header gave Real the lead in the 11th minute - his 57th goal in the Champions League.
Marcelo dinked home a second before Patrik Hrosovsky drove in for Plzen.
Asked afterwards whether he would be in charge for the El Clasico game at Barcelona, the Real coach said: "This question is not for me. We are thinking about preparing for Sunday's game which is very important, and we will go with great ambition."
Real were close to scoring early in the match when veteran defender Sergio Ramos nodded over and then against the post.
Benzema, however, hit the target with his header as he converted Lucas Vazquez's chip to the far post.
Brazil full-back Marcelo then doubled Real's advantage with a chipped finish in the 55th minute after Gareth Bale's delicate pass had sent him clear.
Czech side Plzen impressed at the Bernabeu. Milan Petrzela had a shot blocked by the thigh of Keylor Navas and then fired over from close range, while David Limbersky chipped wide.
They eventually scored 11 minutes from time when Hrosovsky fired into Navas' left-hand corner.
Match ends, Real Madrid 2, Viktoria Plzen 1.
Second Half ends, Real Madrid 2, Viktoria Plzen 1.
Sergio Ramos (Real Madrid) is shown the yellow card for a bad foul.
Foul by Sergio Ramos (Real Madrid).
Jakub Reznicek (Viktoria Plzen) wins a free kick on the right wing.
Marco Asensio (Real Madrid) wins a free kick in the defensive half.
Foul by Radim Reznik (Viktoria Plzen).
Attempt missed. Michal Krmencik (Viktoria Plzen) right footed shot from outside the box is too high. Assisted by Tomas Horava.
Delay over. They are ready to continue.
Marcelo went off injured after Real Madrid had used all subs.
Delay in match Marcelo (Real Madrid) because of an injury.
Substitution, Real Madrid. Mariano replaces Karim Benzema.
Substitution, Viktoria Plzen. Jakub Reznicek replaces Milan Petrzela.
Corner, Viktoria Plzen. Conceded by Nacho.
Attempt missed. Karim Benzema (Real Madrid) right footed shot from the right side of the box misses to the right. Assisted by Luka Modric with a through ball.
Sergio Ramos (Real Madrid) wins a free kick in the defensive half.
Foul by Tomas Horava (Viktoria Plzen).
Goal! Real Madrid 2, Viktoria Plzen 1. Patrik Hrosovsky (Viktoria Plzen) right footed shot from outside the box to the bottom right corner. Assisted by Ales Cermák.
Attempt missed. Lucas Vázquez (Real Madrid) header from the centre of the box is close, but misses to the right. Assisted by Marco Asensio with a cross.
Substitution, Viktoria Plzen. Ubong Ekpai replaces Milan Havel.
Attempt missed. Sergio Ramos (Real Madrid) header from the centre of the box is close, but misses to the left. Assisted by Toni Kroos with a cross following a corner.
Substitution, Real Madrid. Marco Asensio replaces Gareth Bale.
Corner, Real Madrid. Conceded by Radim Reznik.
Attempt blocked. Tomas Horava (Viktoria Plzen) right footed shot from outside the box is blocked. Assisted by David Limbersky.
Corner, Real Madrid. Conceded by Radim Reznik.
Offside, Real Madrid. Gareth Bale tries a through ball, but Luka Modric is caught offside.
Attempt saved. Gareth Bale (Real Madrid) left footed shot from the right side of the box is saved in the bottom right corner. Assisted by Nacho.
Attempt saved. Karim Benzema (Real Madrid) right footed shot from the centre of the box is saved in the bottom right corner.
Attempt saved. Gareth Bale (Real Madrid) left footed shot from the left side of the box is saved in the centre of the goal. Assisted by Toni Kroos.
Attempt missed. Gareth Bale (Real Madrid) left footed shot from outside the box is close, but misses to the left. Assisted by Karim Benzema.
Luka Modric (Real Madrid) wins a free kick in the attacking half.
Foul by Ales Cermák (Viktoria Plzen).
Corner, Real Madrid. Conceded by Milan Petrzela.
Substitution, Viktoria Plzen. Tomas Horava replaces Roman Prochazka.
Attempt missed. Gareth Bale (Real Madrid) header from the centre of the box is close, but misses the top right corner. Assisted by Toni Kroos with a cross following a corner.
Corner, Real Madrid. Conceded by Roman Hubnik.
Foul by Marcelo (Real Madrid).
Radim Reznik (Viktoria Plzen) wins a free kick in the defensive half.
Attempt saved. Luka Modric (Real Madrid) left footed shot from the right side of the box is saved in the bottom right corner. Assisted by Lucas Vázquez.
Toni Kroos (Real Madrid) is shown the yellow card for a bad foul.