Fresh off his Ballon d'Or triumph, Cristiano Ronaldo and his Real Madrid teammates start the second half of the Spanish season looking to put pressure on leaders Barcelona and Atletico Madrid.

Madrid is three points behind the co-leaders with 47.

At the bottom, Valladolid, Rayo Vallecano and Real Betis are in the relegation zone.

Here are five things to know about the Spanish league this weekend:

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KEEPING PACE

With Barcelona and Atletico playing on Sunday, Real Madrid can apply some extra pressure with a victory on Saturday at last-place Real Betis.

Cristiano Ronaldo, who won the Ballon d'Or on Monday, will look to add to his season-high 20 league goals after reaching 30 in all competitions in Wednesday's 2-0 win at Osasuna in the Copa del Rey.

"Now we've reached the most difficult moment of the season because every game is important," said Madrid coach Carlo Ancelotti, who has brought calm to the club after Jose Mourinho's tumultuous term. "We've got many games to play and we have to play well in each of them."

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HIGH-FLYING BARCELONA

Barcelona is feeling good after the first half of the season: Co-leader in the league, on the verge of the Copa del Rey quarterfinals, and through to the second round of the Champions League.

And Lionel Messi is back in form, too.

Messi has shown no signs of struggling to recover his form after a two-month layoff and coach Gerardo Martino seems ready to start the Argentina midfielder rather than bring him off the bench.

"He's in perfect playing condition," Martino said of Messi.

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FINDING NEYMAR

Neymar's adaptation to Barcelona has been slowed by injuries, and now a legal challenge over the Brazil striker's transfer could prove a further disruption.

One club member has challenged Barcelona's transfer fee from Santos, with much of that cost going to a company reputed to be owned by Neymar's father.

After lighting up December with six goals in five games, Neymar is scoreless in two games in the new year.

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BALE'S IMPACT

Much like Neymar, Gareth Bale has shown flashes of brilliance during an irregular start to life in Spain.

But the world's most expensive player — who joined Madrid in a record transfer in the offseason — has made little impact since the start of the calendar year, and is without a goal since November.

Ancelotti said Bale was struggling because of the accumulation of injuries and lack of a real preseason, with the Welshman lacking that instinct for goal in recent games.

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ATLETICO REINFORCEMENTS

Atletico showed itself capable of competing with Barcelona once again following their 0-0 draw on Saturday, but questions over fatigue are certain to begin creeping in with the club still going strong in all three competitions.

Diego Costa is scoreless in four games, while fellow striker David Villa's last goal came seven appearances ago.

Jose Sosa's arrival could ease the burden as the Argentine forward adapted well to the team's play in Tuesday's 2-0 Copa del Rey win over Valencia.

"He'll get better with every day," Atletico coach Diego Simeone said of Sosa, who arrived from Ukrainian club Metalist earlier this month and should be available for Sunday's match against Sevilla.