Barcelona have made their worst start to a season since 2004/05 and have drawn three of their last four games in all competitions, while Real Madrid have not lost in any competition for almost eight months.
Real Madrid have enviously looked on as Barcelona claimed six La Liga titles in the last eight years, but Zinedine Zidane's side can take a huge step towards a first crown since 2012 with victory over their bitter rivals at the Nou Camp in Barcelona on Saturday (2045 IST).
Real have won two Champions Leagues in the last three years, but have been frustrated by Barcelona's recent domestic hegemony, and many of their players have spoken about prioritising their title chase this year.
Unbeaten in all competitions this season, they lead Barcelona and third-placed Sevilla by six points at the top of the standings going into Saturday's Clasico, where a win would open up a nine-point lead over Luis Enrique's stuttering side.
Barca have made their worst start to a season since 2004/05 and have drawn three of their last four games in all competitions, failing to beat Malaga and Real Sociedad in their last league outings.
Luis Enrique called his side's display in their 1-1 draw with Real Sociedad the worst since he took over in 2014 and said it was "a miracle" that his side managed to leave San Sebastian with a point, while defender Gerard Pique questioned their attitude.
Real have not lost in any competition for almost eight months and Zidane is two games away from equalling a club record of 34 games unbeaten.
Both coaches have had to juggle their squads to deal with a raft of absentees this season and Real will be without Toni Kroos and Gareth Bale, although midfield anchor Casemiro is set to return.
Barcelona are boosted by the return of captain Andres Iniesta after six weeks out with a knee injury.
Real's fringe players like Lucas Vazquez, Marco Asensio, Mateo Kovacic and Alvaro Morata have performed admirably when the likes of Cristiano Ronaldo, Karim Benzema, Kroos and Luka Modric have been injured.
Barca have looked far more vulnerable, however, when key personnel have been injured, despite spending some 122 million euros ($128.84 million) on strengthening their squad in the close season.
"Zidane has managed the squad very well, we have the best squad in the world and you can only achieve an unbeaten run like ours with a strong squad," said Real winger Lucas Vazquez.
Defender Nacho added: "In comparison to last season we go to the Nou Camp in a great frame of mind. We're top of the league, we are in very good form and we're very excited about going there to take the three points."
La Liga weekend schedule:
December 3, Saturday
Granada vs Sevilla, 1730 IST
Barcelona vs Real Madrid, 2045 IST
Leganes vs Villareal, 2300 IST
December 4, Sunday
Atletico Madrid vs Espanyol, 0115 IST
Real Betis vs Celta Vigo, 1630 IST