Barcelona are eight points clear at the top of the LaLiga table and in blistering form ahead of their visit to Villarreal.
Real Madrid, on the other hand, slipped up in their last league outing but will expect to return to winning ways when they come back from Club World Cup duty to host bottom side Elche on Wednesday night.
Third-placed Real Sociedad missed the chance to close the gap between them and Los Blancos on Matchday 20 and can make up for lost time by recording an away win at Espanyol.
Meanwhile, Atletico Madrid will hope their visit to a resurgent Celta Vigo bears fruit as they look to stave off the challenge of surprise European contenders Rayo Vallecano, who visit struggling Getafe.
Game of Matchday 21: Villarreal vs Barcelona (Sunday, 8pm)
Barcelona appear to be bulldozing their way towards the LaLiga title and Villarreal are the next team in their path.
The Blaugrana have lost just one of their last 27 top-flight meetings with Sunday’s opponents (20 wins, six draws) and are unbeaten in their previous 13 league visits (nine wins, four draws).
Additionally, Xavi’s men are on a seven-game winning run in all competitions and have kept more clean sheets (15) than any other team in Europe’s top five leagues.
Barca’s Ansu Fati will be hoping to add to his tally of four goals in five meetings with Villarreal.
However, the visitors must be wary of Samuel Chukwueze, who has scored in three of his four home meetings with the Catalan giants.
Real Madrid vs Elche (Wednesday, 8pm)
Real Madrid slumped to a 1-0 defeat at Mallorca last Sunday, giving up precious ground in the race to retain their title.
Carlo Ancelotti’s side can ill-afford further slip-ups — and a clash with bottom-of-the-league Elche appears a promising prospect.
Los Blancos are unbeaten in their last 23 LaLiga home meetings with next Wednesday’s opponents (19 wins, four draws) — their second-longest unbeaten run at the Bernabeu against any team in the competition.
But it remains to be seen whether the Champions League winners’ exploits at the Club World Cup in Morocco will result in a hangover back in the Spanish capital.
Espanyol vs Real Sociedad (Monday, 8pm)
Real Sociedad may go into this clash 18 points clear of Espanyol but their previously impeccable form has hit a slump.
La Real have failed to win any of their last three games in all competitions and have struggled in the absence of David Silva, winning none of the four LaLiga matches he has missed (two draws, two defeats) and claiming victory in 12 of the 16 he has played in (one draw, three defeats).
Espanyol may prove stubborn opponents, recording a league-high nine draws this term.
However, Sociedad boss Imanol Alguacil has not drawn any of his seven LaLiga games against the Barcelona-based outfit — he only has a longer such record against Celta Vigo (eight).
Celta Vigo vs Atletico Madrid (Sunday, 3.15pm)
Given the recent stumbles of Real Madrid and Real Sociedad above them, Atletico Madrid must ensure their own form remains consistent as they seek to make up ground.
In Celta Vigo, Diego Simeone’s men are presented with an opponent that they have enjoyed a strong record against of late.
They are unbeaten in eight meetings (five wins, three draws) and have won five of their last seven league games in Vigo (one draw, one defeat).
They will hope Antoine Griezmann can add to his impressive record of 13 goal involvements in 20 LaLiga clashes with Los Celestes (eight goals, five assists), though he has not registered one in any of his last six games against the Galicians.
Shooting from distance could be a viable option for the Frenchman, given Carlos Carvalhal’s men have conceded a league-high nine goals from outside the box.
Getafe vs Rayo Vallecano (Sunday, 1pm)
Rayo Vallecano have quietly enjoyed an excellent season — they sit fifth in the standings ahead of Matchday 21, just three points off the top four.
Getafe, meanwhile, are 19th, having failed to win any of their last five league matches (one draw, four defeats).
Furthermore, the Azulones have not won or scored in any of their previous three meetings with Los Vallecanos (two draws, one defeat).
Rayo boss Andoni Iraola has been heavily linked with the vacant managerial role at Leeds thanks to his team’s recent performances and he is also unbeaten in his three games as a manager against Getafe (one win, two draws).
The other games on Matchday 21
Cadiz vs Girona (Friday, 8pm)
Almeria vs Real Betis (Saturday, 3.15pm)
Sevilla vs Mallorca (Saturday, 5.30pm)
Valencia vs Athletic Bilbao (Saturday, 8pm)
Real Valladolid vs Osasuna (Sunday, 5.30pm)
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