Real Madrid haven't been at their best this season, while their crosstown rivals Atletico have been in sparkling form.
After they needed some considerable help from the referee to get past Elche 2-1, Real will need to perform at their highest level if they are to get all three points, or even one, against a rampant Atletico when the two sides meet in a La Liga clash at the Bernabeu.
"It is true that against Elche we played badly, but this is another match," Real Madrid manager Carlo Ancelotti said. "We have an important match against a team that are playing well and have won every match.
"They are confident and have a very strong team. It will be a good, tough match. We can play well and win it.
"The group are very motivated. We've spoken about the match in Elche and now we are fully concentrated on the derby. Atletico are two points in front and we have a great opportunity to go ahead.
"We have to take it. I'm happy with the professionalism of the players. Occasionally it can happen that you do not play well and it is important to be self-critical and look forward to the next match."
While Atletico might be in better form, and have picked up 18 points in six games, two more than their city rivals, they have not won in the league against Real since 1999, and the fact that the match will be at the Bernabeu will be an extra advantage for the Los Blancos.
Team News: Gareth Bale is set for a return after missing the last two games through injury. Ancelotti did not reveal whether he would start with the world's most expensive player, but with what's at stake, the Italian might well take a risk.
"With Bale, we are going to see how he is in training," Ancelotti said. "I think he will be available, and if so I will take the decision whether he can start the match or play later on."
Ancelotti also has to make a decision on whether Fabio Coentrao, returning from a long-term injury, can play two games in a week, with fellow left-back Marcelo out injured. The Italian manager might also bring in Raphael Varane in place of Pepe in central defence.
Xabi Alonso is also out for Real, with Atletico set to miss the services of Adrian Lopez.
Key men: Real Madrid: Cristiano Ronaldo of course, after the Portuguese scored both the goals, including a penalty in stoppage time, in the 2-1 win over Elche. Bale, if he starts will be dangerous and with Atletico now knowing enough about the Welshman, the former Tottenham man could take advantage.
Atletico Madrid: Diego Costa has started the season like a house on fire, scoring seven goals already and the Brazilian will be the danger man for Diego Simeone's side.
Where to watch
The match is scheduled for a 1.30 a.m. (IST, Sunday) start with it set for a live telecast on ESPN. You can also catch the match live online by clicking the official link HERE.
Expected lineups: Real Madrid: Diego Lopez; Arbeloa, Varane, Ramos, Coentrao; Khedira, Modric; Bale, Isco, Ronaldo; Benzema.
Atletico Madrid: Courtois; Juanfran, Miranda, Godin, Filipe Luis; Tiago, Suarez, Koke; Turan, Costa, Villa.
Prediction: 3-2 to Real Madrid