We’ve hardly had time to process an eventful fourth round in La Liga, but it’s already time to look ahead to the midweek fifth round of league play. Once again, we’re focusing on two mouth-watering matches. The first features a contest between two top-four sides and the second sees another title contender travel to take on the Spanish Super Cup champions.

Celta Vigo vs. Barcelona

Denis Doyle/Getty Images Sport

After finishing 8th last season, Celta Vigo sits in 4th place in the current campaign. The Galician side has won three and drawn one, giving them 10 points; just two behind league leaders Barcelona, who they host Wednesday evening.

The last match between these two teams at Celta’s Balaídos Municipal Stadium was truly bizarre. In April, Celta had a man sent off for throwing grass in the face of Sergio Busquets. The only goal was Jérémy Mathieu’s header from Xavi’s free-kick. This time around, we’re expecting more goals flying into the net and less grass flying in people’s faces.

Celta Vigo Player to Watch: Nolito

David Ramos/Getty Images Sport

The 28-year-old midfielder one-time Barcelona player could have been our “Player to Watch” for the Catalan side. Barcelona were believed to have been interested in bringing Nolito back to the club, especially after they sold Pedro to Chelsea. However, Celta Vigo’s chairman said Barca never made an offer. So, Nolito is still at Celta and all he’s done is average a goal a game so far this season. We’re sure he’d love to keep that streak alive with a match-winner against the team for which he made his professional debut five years ago.

Barcelona Player to Watch: Marc-André ter Stegen

Paolo Bruno/Getty Images Sport

With Claudio Bravo still injured, ter Stegen will be Barcelona’s Champions League and La Liga keeper for the next several weeks. Barça Manager Luis Enrique took the blame for the wonder-goal from midfield that Roma’s Alessandro Florenzi scored against ter Stegen, saying he wants Barca’s keepers to play high up the pitch when his team has possession.

However, ter Stegen had to answer the questions himself after he failed to claim a cross against Levante, leading to that team’s only goal in Barcelona’s 4-1 win on Sunday. The 23-year-old German keeper will have to be on his game Wednesday night against a Celta Vigo side that has scored ten goals in four matches, two more than Barcelona.

Team Under the Most Pressure: Barcelona

Alex Caparros/Getty Images Sport

No one expected Celta Vigo to be in fourth place after four matches. For that reason, they should be able to really express themselves in this match by coming out and attacking Barcelona. Luis Enrique will be a bit relieved knowing that Gerard Piqué will be able to make his La Liga debut, having served his four-match suspension. Still, Enrique will be well aware that a loss to the club he managed two seasons ago would take Celta, and possibly arch-rivals Real Madrid, to the top of the table. That brings us to our second “Match of the Week”.

Athletic Bilbao vs. Real Madrid

David Ramos/Getty Images Sport

Real Madrid will be hoping that the third time’s the charm when they travel to take on Athletic Club at the San Mamés Wednesday night. They’ve only earned one point from their two previous trips to Athletic Club’s new stadium.

Athletic Bilbao Player to Watch: Aritz Aduriz

David Ramos/Getty Images Sport

The 34-year-old scored the winner against Real Madrid in last season’s clash in the Basque Country and has been unstoppable for Athletic Club lately. Aduriz scored four of his team’s five goals against Barcelona in the Spanish Super Cup, helping Athletic Club win its first trophy in 31 years.

He scored twice in last week’s Europa League victory over Augsburg and has three goals in three appearances so far in La Liga. Sergio Ramos’ fitness is still up in the air after nearly dislocated his shoulder in Real Madrid’s Champions League victory over Shakhtar Donetsk, but regardless of who plays in central defense, Aritz Aduriz is going to be a handful. Real Madrid’s record of four consecutive clean sheets is very much under threat.

Real Madrid Player to Watch: Isco

Gonzalo Arroyo Moreno/Getty Images Sport

The 23-year-old Spaniard has started Real Madrid’s last three matches since James Rodríguez got injured while on international duty with Colombia. In Rafael Benítez’s 4-2-3-1 system, Isco has been playing centrally in the midfield three, but in those games, he’s recorded just one assist and no goals.

Compare that with James’ two goals and one assist in just two appearances this season, and it’s easy to understand why Isco is under pressure to perform. Offensively, Real Madrid still relies on lightning-quick attacks to score goals. Unlike James and Gareth Bale (also out injured), Isco just seems to linger a bit too long on the ball. Isco needs to make the most of this opportunity to impress if he wants to keep his starting place when Real’s injured stars return.

Team Under the Most Pressure: Real Madrid

Gonzalo Arroyo Moreno/Getty Images Sport

In truth, both teams are under pressure, albeit it for different reasons. Both Athletic Bilbao and Real Madrid are playing in Europe and the difference in the clubs’ squad depth is starting to show. If Real loses the likes of James Rodrígue, Sergio Ramos, or Gareth Bale to injury, Rafa Benítez can bring on Isco, Pepe, or 32-million euro summer signing Mateo Kovačić.

Athletic Bilbao’s Ernesto Valverde, obviously, doesn’t have such options. After last Thursday’s Europa League game, Valverde opted to rest Aritz Aduriz and new addition Raúl García against Villarreal so they would be ready for this match against Real Madrid. The result was a 3-1 defeat with Athletic Club’s only goal being scored by, that’s right, Aduriz who, along with Garcí, were forced to enter the game after one hour when Athletic Club were losing 2-0.

Many supporters view Sunday’s result as a wasted opportunity. With Athletic Club currently in 13th place, Valverde could really use a home win Wednesday against Real Madrid. However, having already given supporters of the Basque club their first trophy in 31 seasons and getting them off to a winning start in the Europa League, Valverde isn’t under any real pressure and would probably settle for a point. For Rafa Benítez and Real Madrid, on the other hand, every draw feels like a defeat. Only their first win at the new San Mamés will do.

Read more from Stephen Skiles