Real are top of the table on goal difference, as a result of Sunday's 5-0 slaughter of bottom team Xerez, in which Cristiano Ronaldo scored two more goals.
Ronaldo is joint top of the scorers' chart with David Villa of Valencia, both on four goals.
Real's Ruud Van Nistelrooy is likely to be out of action for a couple of weeks. The Dutch veteran, who was out for 10 months after a knee ligament operation, came off the bench and scored the fifth goal against Xerez - but pulled a muscle in his left calf in the process.
Real will again be without suspended defender Pepe.
Villarreal have just two points, their worst start to a season since 1998. However, midfielder Santi Cazorla said on Sunday that 'I am sure that we will give Madrid a really hard game.'
Also Wednesday, high-flying Bilbao will be away to Tenerife, whilst Valencia face Getafe and troubled Atletico Madrid are at home to Almeria.
Atletico have just one point to their name. Failure to convincingly beat Almeria will bring the wrath of the Estadio Calderon don on embattled coach Abel Resino.