Madrid (Spain), Apr 24 (IANS): The 31st round of matches in La Liga will be held this week, with three games on Tuesday night, including one which will have a huge impact on who plays next season's UEFA Champions League.

Fourth-placed Real Sociedad visit Real Betis, who sit one place and six points behind them in fifth, and who travel to San Sebastian after a worrying run of three defeats in four matches.

Real Sociedad fought back to beat Rayo Vallecano at the weekend, and their recent form has also been uneven, but a win for the Basque side would lift them nine points clear of Betis and put them very much on track for a place in next season's Champions League, reports Xinhua.

Defeat for Betis could see them drop out of the top six if Athletic Club and Villarreal win their respective matches later in the week.

Striker Borja Iglesias has been struggling for form, and they are missing the creativity of injured midfielder Nabil Fekir.

Real Madrid's title ambitions suffered a probably fatal blow when Barcelona beat Atletico Madrid 1-0 on Sunday to keep their 11-point lead at the top of the table.

Carlo Ancelotti will maintain his policy of squad rotations ahead of their Champions League semifinal against Manchester City for his side's visit to Girona.

Girona are 11th in the table with an eight-point cushion over the relegation zone and probably need just one win to assure their survival for another season in the top flight.

Things are a lot tighter for Cadiz, who are just two points above the relegation zone, but the team from the southwest will look to their solid home form to see them through against Osasuna.

Osasuna travel after beating Betis last Friday, but with the Copa del Rey final just 11 days after Tuesday's game, they could be excused for having their attention elsewhere.

Wednesday sees some key matches, such as Barcelona's visit to Rayo Vallecano, while Getafe host Almeria and Valencia entertain Valladolid in vital matches to avoid relegation.