The last time eternal rivals Barcelona and Real Madrid met, at the Spanish Super Cup in August, there was an imbalance in the power dynamic between the pair of Spanish giants.

Real Madrid was coming off a season in which it won La Liga and the UEFA Champions League title. Barcelona, on the other hand, was emerging from a summer of turmoil. It had just sold Neymar -- the second-best player on the team but third-best player in the world -- to Paris Saint-Germain. And instead of investing in more big-name players to replace him, Barca signed players such as prodigal son Gerard Deulofeu and Paulinho, who had been plying his trade in China. Gerard Pique even said he felt Barcelona was "inferior" to Real, a statement that amounts to blasphemy among fans of the Blaugrana. Real beat Barcelona 5-1 on aggregate over two Spanish Super Cup legs, and it seemed like it was set for another season of dominance.

Fast forward four months, and Barcelona holds a commanding 11-point lead over Real Madrid in La Liga and with it an opportunity to put one hand on the La Liga title while simultaneously finishing off its rivals' title hopes with a win in El Clasico on Saturday at the Santiago Bernabeu in Madrid. This was not how the first La Liga Clasico of the 2017-18 La Liga campaign was supposed to go down.

In those four months, the two powers of Spanish soccer have seen massive reversals of fortune. Following the Super Cup loss, Barcelona began a run it's still on. The Blaugrana are undefeated in La Liga with 13 wins and three draws, and they won their Champions League group without a loss. An embarrassment of riches in attack that includes Lionel Messi, the world's best player, and Luis Suarez has mitigated the absence of Neymar, while once-maligned signings such as Paulinho have chipped in with top performances and goals (seven, in the case of Paulinho).

In the meantime, Real Madrid has trended in the opposite direction, starting with that Super Cup tie in August. In the first leg, an angry Cristiano Ronaldo shoved a referee and earned himself a five-match ban. That led to a massive goal drought from the typically reliable Ronaldo. Ronaldo had 10 goals in La Liga at this stage last season. This season, he has four. And he isn't the only Madrid attacker who has seen a dip in form. Gareth Bale and Karim Benzema had five and four goals, respectively, at this point last season. This season, they have two apiece. This lack of goals is one reason Real sits fourth in La Liga and finished second in its Champions League group.

To make matters more difficult for Madrid, Barcelona's defense is having an outstanding season. The Blaugrana have allowed just seven goals in La Liga this season, and they haven't allowed any from set pieces. The attention to defensive detail brought in by manager Ernesto Valverde over the summer has changed the way Barca defends. This Barcelona team is more disciplined defensively, thanks in part to Paulinho, an excellent stopper in midfield. Another major reason for the defensive success is the play of keeper Marc-Andre Ter Stegen, who is finally growing into the world-class player he showed the potential to be when first signed.

Real is catching a small break in this department, though. Barcelona central defender Samuel Umtiti will miss the match with an injury, and he will likely be replaced by Thomas Vermaelen or Javier Mascherano. That small weakness in Barcelona's defensive chain could be enough to help Madrid find a breakthrough and maybe a win.

But like all Clasicos in recent years, this match has the potential to be decided by Messi or Ronaldo. A top performance by either can be enough to lift his side to a win, while a poor performance by either can be enough to saddle his side with a loss. Their form will have a major impact on the result Saturday, which would seem to favor Barcelona.

While Ronaldo is fighting to escape his current slump, Messi is putting together a fantastic season. The Argentinian attacker has scored 14 goals for the league lead and added five assists. His 19 goals contributed (goals scored and assisted combined) are eight more than any other player in Spain this season. Basically, Messi is being Messi, and when Messi is Mess, Barcelona tends to win.

Although Real Madrid's players have struggled individually and collectively throughout the season so far, they have regained some form as of late. Madrid finally seems to be back to full health, and Bale should be ready to make a return to the pitch Saturday following an extended absence. It also won the Club World Cup in Abu Dhabi last week, which, although not a necessarily a big deal, should provide a nice morale boost. 

All told, Barcelona is the favorite heading into Saturday. But that ultimately doesn't mean much. Ignoring the whole rivalry "throw out the records" trope for a moment, Madrid has enough talent to beat any team in the world, regardless of the form with which it enters the match. If Ronaldo and company have their heads on straight this weekend, they can come away with a win, even if Barcelona plays a great game.

Considering any chance of winning another La Liga dies with a loss or draw at the Bernabeu, I expect Real Madrid to be ready.

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Cy Brown writes about football, golf, soccer and other stuff for Sports on Earth. Follow him on Twitter @CEPBrown.