Four things to look out for on Spain's matchday 19

MADRID, Jan. 12 (Xinhua) -- The Spanish Liga Santander reaches its halfway point at the weekend with Barcelona nine points clear at the top of the table; here are some things to keep an eye out for in match day 19.

1 Real Madrid home form to improve?

Real Madrid's 2-2 draw at home to second division Numancia on Wednesday means they have failed to win half of their home games this season. Many sides once saw the Santiago Bernabeu as a fortress they were assured of leaving empty handed, but now teams seem to believe they can exploit Madrid's leaky defense, misfiring attack and a set of fans who are increasingly impatient with their players.

Zinedine Zidane insists he is happy with his current squad, but Cristiano Ronaldo and Karim Benzema have just 6 league goals between them all season. The return of Gareth Bale in Vigo showed he can add pace and punch and he will need to do so again on Saturday, because a failure to beat a Villarreal side that has lost star striker Cedric Bakambu could leave Zidane's job increasingly in peril.

2 Barca to continue their form in San Sebastian

Real Sociedad's Anoeta Stadium has been a difficult place for Barca to visit in recent seasons, but Sunday's game comes at probably the best possible time for Ernesto Valverde's league leaders. Barca cruised past Celta Vigo in the King's Cup on Thursday night to book their place in the quarter-finals of the competition, while a 3-0 win at home to Levante at the weekend leaves them nine points clear of Atletico Madrid.

Real Sociedad meanwhile are stumbling after a good start to the season and although Eusebio Sacristan's side can play neat football, poor defending and goalkeeping errors are costing them dearly.

If your defense is shipping goals the last people you want rolling up at your front door are Leo Messi and Luis Suarez, so anything but a comfy win for Barca on Sunday would be a surprise.

3. Ipurua to test Atletico's credentials?

Atletico Madrid look increasingly like the main alternative to Barca as possible league champions, but Saturday provides a huge test for Diego Simeone's men as they visit Eibar's small Ipurua Stadium.

Atletico are without the suspended trio of Gabi Fernandez, Diego Godin and Diego Costa and although Thomas Party and Jose Gimenez can be relied on to perform, the experience of the missing trio would have been useful against one of Europe's most in-form sides.

Six wins and a draw from seven games have lifted Eibar to seventh in the table and with players such as Ivi Alejo, Takashi Inui and Sergi Enrich relishing the moment, this is a huge test for Atletico's title hopes.

4. Vietto to revitalize Valencia?

Football can be a strange sport: just ask Valencia striker Luciano Vietto who tried and failed all season to score for Atletico Madrid and was shipped out on loan to Valencia to allow for the incorporation of Diego Costa in the Atletico squad.

Vietto made his debut and missed another chance as Valencia beat Girona at the weekend, but then scored a hat-trick as his new side demolished Las Palmas in the Cup.

His arrival and that of Francis Coquelin should give more depth to a squad clearly needing new arrivals, while Goncalo Guedes' excellent form gives hope that Marcelino Garcia's side are in the title race for the long haul.

Marcelino got the best out of Vietto when the pair were at Villarreal together and Valencia fans will be hoping the relationship remains fruitful at Mestalla. Enditem