Reals Betis and Sociedad are locked together on nine points in upper mid-table, but the Basques poor away form could be their undoing.
Sociedad are yet to draw this season, winning three at Anoeta and losing three on the road. Goalkeeper Claudio Bravo is still unavailable but rates replacement Enaut Zubikarai highly.
"I have great confidence in him. Everyone knows how he is able to perform.”
Hosts Betis are hoping to rediscover the form they showed in the early weeks, after a controversial 3-2 defeat to Atletico Madrid and 4-0 rout at the hands of Malaga.
"I do not believe that there are orders from above to hurt some teams and benefit others,” commented defender Ignacio Perez.
"However, if the referee cannot rise to the occasion, there must be an internal wake-up call so that the next game will be better.”