MADRID (AP) -- The Spanish league will be dominated by the Barcelona vs. Real Madrid "Clasico." In other matches, Atletico Madrid hosts 15th-place Real Betis and fourth-place Villarreal plays eighth-place Valencia. Here are five things to know about this weekend's games:
Madrid coach Carlo Ancelotti is still tinkering with his preferred starting lineup: benching captain Iker Casillas in favor of goalkeeper Diego Lopez in league matches but not in the Champions League and appearing indecisive as to his attacking formation.
After his team's 2-1 win over Juventus he praised striker Karim Benzema for giving Andrea Pirlo a hard time -- but the Frenchman did not score. Asked if he already knew who would be his striker against Barcelona, the coach answered "yes," curtly.
He then added that Gareth Bale -- who has been struggling with an injury since joining from Tottenham -- was now ready to start a match.
The buzz around Spain is whether Ancelotti will substitute on-form pass-provider Angel Di Maria, who plays in Bale's current position, or whether the coach's hint was an indication that the Wales international will instead replace Benzema in attack.
ANYTHING CAN HAPPEN
League matches against Barcelona are intense and unpredictable encounters, according to Madrid defender Sergio Ramos.
"When assessing a 'clasico' you must not take recent results too much into account," he said. "Rivalry is always at its most intense in these matches. At this level, anything can happen."#
Although recent Barcelona signing Neymar has yet to play in such an encounter, the Brazil striker said he is already aware of how important clasicos are for players.
"I think these are matches that need no explanation," Neymar said. "This will be my first 'clasico' and I want to make a big impact on my debut, preferably with a win."
Two days ahead of the 'clasico,' Barcelona coach Gerardo Martino has many doubts about his squad to contend with.
The Champions League match against AC Milan should have been a good rehearsal, but it ended in a disappointing 1-1 draw rescued, once again, by a moment of magical improvisation by Lionel Messi.
The much hoped-for scoring chemistry between the Argentina forward and Neymar has yet to materialize. And the club's defense still looks fragile.
Captain Carles Puyol did not play against Milan, and Gerard Pique is in doubt for the Madrid match after experiencing "discomfort in the hamstring in his left leg," the club said.
Javier Mascherano, whose injury last season precipitated Barcelona's Champions League decline, has acknowledged the goal conceded at Milan was his mistake.
"I think it's my fault," he said. "In a match like that, you can't commit this type of error."
With so much at stake in the league this weekend, referees will need to be alert to players trying to take unfair advantage by overreacting to challenges, especially in the penalty area.
The subject of trying to get the better of referees received a high profile when Barcelona striker Neymar was criticized by Celtic coach Neil Lennon after he writhed on the ground in apparent agony after team captain Scott Brown kicked him in a Champions League match.
Chelsea coach Jose Mourinho called such behavior "disgraceful."
Madrid beat a 10-man Juventus on Wednesday after Ronaldo fell to the ground and rolled around, getting Juventus defender Giorgio Chiellini sent off on a straight red card after apparently just brushing his hand across the Portugal forward's face. And Gareth Bale gained an unconvincing penalty by falling in the box after a run alongside Malaga defender Weligton Oliveira in a previous league match.
Atletico Madrid is only one point shy of league leader Barcelona, and it leads third-place Real Madrid by two, keeping things tight at the top.
Its emphatic 3-0 Group G Champions League win against Austria Vienna highlighted the scoring talent of Diego Costa, who netted the ball twice.
Should it trounce lowly Betis and Barcelona draws against archrival Madrid, then coach Diego Simeone could provide Atletico fans much to cheer about.