Lionel Messi is the best player in the world "by a large margin", Barcelona legend Ronald Koeman said ahead of Saturday's Clasico against Real Madrid.

Koeman, who played for Barca between 1989 and 1995, believes Messi's genius marks him out above rivals such as Madrid's Cristiano Ronaldo.

The Southampton manager explained he thinks Barcelona are favourites for the Clasico due to their 'MSN' strikeforce, with Messi supported by Neymar and Luis Suarez.

"Barca have the best players at the moment," Koeman told Barca TV. "They have the three players up front and their performances are really impressive, but they still have [Sergio] Busquets, [Andres] Iniesta, [Gerard] Pique.

"I think the heart of the Barca style is still those Catalan players, well coached of course by really good coaches. I think it is also important that there is calmness there from the board.

"Suarez - I know him since his time at Ajax. He showed what a great player he was, too good for the Dutch league, so he went to Liverpool. He had a difficult start at Barcelona but he has shown since then that he is a fantastic player.

"Neymar has his qualities. He is still a young player but he is going to explode one day. He is very quick, he is a goalscorer, he's got all the qualities you want in an attacking player.

"Messi is Messi. You can say a thousand things more about him but Messi is the best in the world, by a large margin. He is capable of doing it in a split-second, he is capable of doing amazing things by himself. Obviously, he needs other players as well, to help him and give him the ball.

"Barcelona are the favourites, I think. Madrid, I don't really see them being as strong as they need to be to catch up with Barcelona. Both teams are in the Champions League, but I think in La Liga there is too much difference."

Koeman also reminisced about the Clasico games he remembers as a player, with one match in particular standing out from the rest.

"I've got great memories. The most special game that you can play in, there's always a lot of great rivarly playing at Camp Nou against Madrid - there isn't a bigger game," he added.

"If I had to pick one [Clasico] I'm going to pick, I don't know if you expect this one, but it's the first one. We won 3-1, [I scored] two penalties, one penalty that I had to take again.

"I scored three penalties against Madrid, who else can say that?"