Real Madrid need a victory at Athletic Bilbao to keep the pressure on leaders Barcelona as they look to get their LaLiga title challenge back on track.
The Blaugrana won their first trophy under head coach Xavi in last Sunday’s Supercopa de Espana triumph over their old foes and return to league action by hosting Getafe.
Elsewhere, third-placed Real Sociedad are snapping at Los Blancos’ heels and visit Rayo Vallecano next, while Atletico Madrid welcome Real Valladolid to the capital.
Second-bottom Sevilla, meanwhile, prepare for a potentially season-defining clash as they host fellow relegation candidates Cadiz.
Game of the week: Athletic Bilbao vs Real Madrid (Sunday, 8pm)
Real need a positive result in Bilbao and history is on their side in this fixture.
Los Blancos have not lost any of their last 14 LaLiga clashes with Athletic (10 wins, four draws) and have won each of the previous five top-flight encounters.
However, the Basque outfit knocked Carlo Ancelotti’s men out of last season’s Copa del Rey at the quarter-final stage and are unbeaten in their last four home fixtures without conceding a goal.
Ancelotti will hope Karim Benzema can breach Ernesto Valverde’s defence on Sunday — the French Ballon d’Or winner has scored more goals against Athletic than any other opponent in the competition (16).
Barcelona vs Getafe (Sunday, 5.30pm)
League leaders Barcelona will hope to maintain their unbeaten home record against Getafe in LaLiga (13 wins, four draws) — they only boast a better record against Elche of the teams currently in the Spanish top flight (24 home games unbeaten).
The Blaugrana have yet to lose a league match at the Camp Nou this term (six wins, two draws) and have scored in all but one of their 16 LaLiga games so far.
Getafe, meanwhile, have lost three on the bounce and sit only a point from the drop zone.
The Azulones’ head coach — Quique Sanchez Flores — has not triumphed in any of his last seven LaLiga meetings with Barca (two draws, five defeats).
Rayo Vallecano vs Real Sociedad (Saturday, 1pm)
Sociedad are just three points behind second-placed Los Blancos heading into Matchday 18.
Encouragingly for La Real, they have not lost in any of their last seven meetings with Rayo Vallecano (three wins, four draws).
Imanol Alguacil’s men also come into the game in exceptional form, winning eight on the bounce including a 1-0 victory over Mallorca in Tuesday’s Copa del Rey tie.
Rayo boss Andoni Iraola has faced Sociedad four times as a manager without winning (one draw, three defeats) — he only has a worse record against Real Betis and Sporting Gijon.
Atletico Madrid vs Real Valladolid (Saturday, 5.30pm)
Atleti are in dire need of consistency and a visit from Valladolid could prove the perfect springboard for a positive run.
The Rojiblancos are enjoying their longest-ever unbeaten run against Saturday’s opponents (11 wins, one draw) and have won each of their previous six home meetings, keeping clean sheets in the last four.
Valladolid, meanwhile, have lost their last four outings, failing to score each time.
Victory for the hosts would be a boost for a side that are enduring their worst campaign under Diego Simeone at this stage of the season with 28 points from 17 games.
Sevilla vs Cadiz (Saturday, 8pm)
Sevilla are 19th going into Matchday 18 — one point and one place behind Cadiz.
The importance of securing victory can hardly be overstated and Jorge Sampaoli’s side will look to lean on their strong record against their Andalucian neighbours — they have not lost any of their last 10 league meetings (five wins, five draws).
The hosts will hope Youssef En-Nesyri can maintain his positive scoring streak against Los Piratas, having netted four times (including a hat-trick) in his two games against them at the Estadio Ramon Sanchez-Pizjuan.
Additionally, Cadiz head coach Sergio Gonzalez has never claimed victory over Sevilla as a manager in nine attempts (four draws, five defeats) — he only has a worse record against Real Madrid (two draws, nine defeats).
The weekend’s other games
Mallorca vs Celta Vigo (Friday, 8pm)
Espanyol vs Real Betis (Saturday, 3.15pm)
Villarreal vs Girona (Sunday, 1pm)
Elche vs Osasuna (Sunday, 3.15pm)
Valencia vs Almeria (Monday, 8pm)
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