Villarreal have won just once in La Liga this season and have lost all three of their Champions League games, but Levante defender Javi Venta is wary of the threat posed by his former team nevertheless.
He said in AS: "It's true they aren't in good form in the league, but we are well aware that it's going to be a very difficult game."
Valencia take on improving Athletic Bilbao in another interesting encounter, while Atletico Madrid coach Gregorio Manzano faces one of his former sides in Real Mallorca. Atletico have failed to score in five of their seven league matches this season but won the other two games 4-0.
Real Betis, having won their opening four matches, will now attempt to end a run of three successive defeats when they host fellow La Liga newcomers Rayo Vallecano in one of Sunday's games.
Also, Real Sociedad take on Getafe and Real Zaragoza go to Osasuna.
On Saturday, Real Madrid went top of the La Liga, seeing off Malaga 4-0 before Barcelona were held to a goalless draw by Sevilla.
Sporting produced a stunning first-half display to secure their first win of the season in a 2-0 success over Granada.
Espanyol secured their second consecutive 1-0 win on the road thanks to Sergio Garcia's second-half winner against rock bottom Racing Santander at El Sardinero.