MADRID, March 22 (Reuters) - Key head-to-head battles in Sunday's "Clasico" between Real Madrid and Barcelona at the Bernabeu stadium (2000 GMT). Real players listed first:
CRISTIANO RONALDO v LIONEL MESSI
Ronaldo, 29, and Messi, 26, are two of the most lethal goalscorers in soccer history. Messi's season has been disrupted by a two-month injury layoff but he has still managed 31 goals in 31 appearances in the three main competitions this term and is now Barca's all-time top scorer.
Portugal captain Ronaldo, who has succeeded Messi as World Player of the Year after four consecutive awards for the Argentina forward, has 41 goals in 37 games, including 13 in the Champions League.
Both players have the freedom to roam and are often most dangerous driving down the centre. Their styles are very different.
Messi plays with schoolboy enthusiasm, making darting runs and exchanging quick passes with team mates. Ronaldo is more of a showman, making muscular charges down the pitch, and his powerful, swerving freekicks are a threat from any range.
GARETH BALE v NEYMAR
Real and Barca's marquee signings of the close season have had indifferent and injury-hit starts to their stints in Spain.
Bale, 24, who became the world's most expensive player when he joined from Tottenham Hotspur, is starting to settle into his role on the right wing and has netted 14 times in 24 appearances overall.
The Wales winger has also made 14 goal assists and appears to be developing a fine understanding with fellow forwards Ronaldo and Karim Benzema.
Neymar, 22, has blown hot and cold since joining from Santos and although the Brazilian scored the opening goal in Barca's 2-1 'Clasico' win at the Nou Camp in October he has only netted once since the turn of the year and 11 in 30 appearances overall.
XABI ALONSO v XAVI
The Spain midfielders, who operate in slightly different roles, are considered irreplaceable. Playmaker Xavi, 34, is the heart of Barca and Spain's possession-based football and covers a huge amount of ground in a match, linking up play and creating chances.
He has been used more sparingly this season as he approaches the end of an illustrious career.
Alonso, 32, plays in a deeper, more defensive role, typically alongside Luka Modric, but his passes, especially balls from deep in his own half to launch counter-attacks, are a major feature of his side's play.
Real looked lost without him when he missed the start of the season through injury.
SERGIO RAMOS v GERARD PIQUE
Centre backs Ramos, 28, and Pique, 27, will be at the heart of the Spain defence as they seek a second straight World Cup triumph at the finals in Brazil starting in June.
Athletic, committed and a tough tackler, Ramos has transformed himself into one of the world's top central defenders since switching over from right back and is a real threat at attacking corners but sometimes throws himself too hastily into a challenge.
An elegant and composed player, Pique is never happier than when joining the attack as an auxiliary striker chasing late goals. He lacks pace but makes up for it with great timing in the tackle and is an astute passer.
DIEGO LOPEZ v VICTOR VALDES
Lopez, 32, has coped well with the unenviable task of alternating with fan hero Iker Casillas in goal since he was hastily brought in after the club captain was sidelined by injury in January 2013.
He has made some vital interventions this season and also deals well with aerial threats, an area of Casillas's game where he has not always convinced.
Valdes, 32, is widely recognised as one of the best goalkeepers in the world. He is an imposing presence who acts as the starting point for much of Barca's possession play and his distribution from the back is one of the aspects of the game they spend a lot of time working on in training. (Compiled by Iain Rogers, editing by Patrick Johnston)