When Real Madrid faced Barcelona two weeks ago in El Clasico, they did so without having to deal with star striker Robert Lewandowski, who was injured for the Copa del Rey Final.
Even though Barcelona won without him and with Ferran Torres at striker, they were pushed much closer than in the other Clasicos this season and did seem to miss Lewa's larger-than-life presence off the ball.
When Lewandowski faced Real Madrid earlier this season in El Clasico, he scored two goals and was unstoppable to the overmatched Madrid defense in what ended up being a 4-0 win on the road for the Blaugrana.
Now at home at the Olympic Stadium this Sunday, Barcelona have a chance to seal the LaLiga title by beating Los Blancos.
Lewandowski has a point to prove and added motivation. Barcelona were knocked out of the Champions League semifinals at mid-week by Inter Milan, and Lewa was a part of the defeat. Even though he didn't start the game due to injury, Lewandowski was brought in by Hansi Flick before the extra time period. He missed a couple of easy chances and had a generally poor game, with Barcelona losing control of the match after his inclusion into the bout.
Robert Lewandowski will like his matchup vs. Aurelien Tchouameni
So now with LaLiga on the line, Lewandowski will want to bounce back now that he's healthier and ready to start against a team he has consistently gotten the better of as a pro, whether at Barcelona or at Borussia Dortmund.
Standing in his way on Sunday is a tantalizing matchup against a broken Real Madrid defense. Antonio Rudiger's suspension (and surgery) take him out of the equation and leave Raul Asencio as the only true center back.
Aurelien Tchouameni has been brilliant in recent weeks as a defensive midfielder, including scoring in the last Clasico, but now he is back at center back - a position he has struggled mightily in this season.
To wit, Tchouameni was torn to shreds by Barcelona in an earlier meeting in the Spanish Supercup Final.
Tchouameni's inability to fundamentally play the position off the ball has been exploited by top forwards, and Raphinha and Lewandowski are two of the best in the business at making sharp movements and outsmarting defenses.
So in a lot of ways, Sunday's title-decider comes down to a key one-on-one matchup between the legendary Lewandowski and a talented Tchouameni, albeit playing in a position that isn't truly is.
This switch for Real Madrid is out of necessity, and they need Tchouameni to, even for one game only, provide the same brilliance at center back that he has as a 6 over these past several weeks in which he has resumed being indispensible to Carlo Ancelotti.
One lapse of concentration of a corner, one slip-up, one false step, one mistracked run, and Robert Lewandowski can sink Real Madrid. That's the margin for error.
That's what is at stake on Sunday when these two hated rivals take the field one last time this season, with Barcelona looking to make it a perfect four from four in Clasico victories and seal up the second major domestic trophy of the campaign.
The pressure is on Tchouameni, because, as a defender, he can't make a mistake. If Lewandowski misses a chance, he can make it up.
If Tchouameni makes a bad pass, a clumsy touch, or, even easier, a blunder off the ball that leads to a Lewandowski goal or assist, there is no second chance. A single goal margin could easily be the difference in Real Madrid winning or losing LaLiga outright this Sunday.