Madrid, Jan 6 (IANS): Matchday 16 in La Liga comes after an intense week of Copa del Rey action, which will have given some sides confidence while leaving others with a few things to think about.

Here are the four things to look out for in Spain this weekend:

PROBLEMS FOR BARCA AGAINST ATLETICO MADRID

Although the return of defender Ronald Araujo after injury was good news for Barca coach Xavi Hernandez, that was Xavi's only reason to be cheerful ahead of Sunday's visit to play Atletico Madrid.

Barca needed extra time to get past the third tier, CF Intercity in midweek and after Araujo was taken off, they looked weak at the back. They also missed chances without Robert Lewandowski leading the line, with both Ferran Torres and Memphis Depay misfiring.

That's important as Lewandowski is suspended for the Atletico game along with Jordi Alba and they are two key absences that weaken Xavi's starting 11 as Barca look to recapture their pre-World Cup form.

DIFFERENT MOODS AT ATLETICO

Atletico cruised into the last 16 of the Cup with a 2-0 win in Oviedo and coach Diego Simeone will have been pleased with another all-action display from Antoine Griezmann, who has gained in confidence after the World Cup, reports Xinhua.

Alvaro Morata continues to be a hard-running partner in attack and although Joao Felix's future with Atletico looks far from certain, with interest from the Premier League, the departure of the talented but inconsistent Portuguese probably won't upset Simeone too much, especially as youngster Pablo Barros is staking an ever-stronger claim for a regular starting place.

VILLARREAL TO TEST REAL MADRID

Villarreal seem to have steeled down under Quique Setien after a difficult start for the former Betis and Barca coach in the dugout. The World Cup break has allowed Setien to work with his players after the shock departure of Unai Emery, and it seems they are now adapting to the demands of his passing game, while the return of Gerard Moreno also boosts their effectiveness in attack.

Real Madrid have won their first two games back since the World Cup, but have not been convinced, needing a late penalty to help them past Valladolid and sneaking past lower division Cacereno 1-0 in the Cup this week.

Carlo Ancelotti complained about the pitch in Caceres, forgetting that less-than-perfect playing surfaces are the norm for the vast majority of footballers at this time of year.

Presumably, the pitch at the recently reformed Estadio de la Ceramica will be more to his liking.

REAL SOCIEDAD TO KEEP UP CHALLENGE IN ALMERIA

Real Sociedad eased into the last 16 of the Cup with a 1-0 win against Logrones in midweek, with coach Imanol Alguacil resting several first-team regulars.

Two players who didn't rest were midfielders Mikel Merino and Brais Mendez, with Mendes in outstanding form since his move from Celta over the summer.

The depth of their squad and the excellent football they are currently playing implies the side from San Sebastian is the team that looks most likely to get close to Barca and Real Madrid in the title race, although they have started well and faded slightly in their last two campaigns.

With Mikel Oyarzabal on his way back to full fitness, the side from San Sebastian should have enough to take three points from their visit to Almeria.