La Liga Preview: Rayo v Barcelona
Gerardo Martino's men have made an excellent start to the season, picking up 12 points from their first four games while scoring 14 goals.
Reigning champions Barca sit joint top of the table with Atletico Madrid, and make the trip to face another side from the Spanish capital to whom they have not lost since 2002.
The Catalan club won both outings between the two sides in emphatic fashion last season, dishing out a 5-0 thrashing at Rayo in October 2012, before easing to a 3-1 success at the Camp Nou in March.
Their visit to the Estadio del Rayo Vallecano in 2011-12, meanwhile, resulted in a 7-0 success.
Lionel Messi scored four goals in last term's encounters, and the Argentine talisman approaches this contest in fine form, having netted his 24th hat-trick for Barcelona in a 4-0 win over Ajax in the UEFA Champions League on Wednesday.
Messi, who has also scored six goals in three league appearances this season, will once again be expected to play a prominent role in the Barca side, but Martino's men will be without Jordi Alba, who has a hamstring injury.
Carles Puyol (knee) is close to recovery, but this game is like to come too soon for the Barcelona captain, while Ibrahim Affelay (thigh) is also out.
Rayo have endured a dismal start to the campaign, tasting victory in just one of their four matches thus far.
That win came on the opening day of the season against newly-promoted Elche, but since then Paco Jemez's men - who finished eighth last term - have collapsed, conceding 12 goals in their last three games.
Striker Lass Bangoura, sent-off in the defeat to Levante, is still suspended for Rayo, while Iago Falque (groin) and Jose Carlos (knee ligament) are both long-term absentees.