Lionel Messi class continues off the field as Barcelona star wishes Iker Casillas well after heart attack

Lionel Messi put Barcelona-Real Madrid rivalry aside with a classy tribute to Iker Casillas after he suffered a heart attack at training.

The Real Madrid and Spain legend now plays for FC Porto, and the Portuguese club confirmed the 37-year-old goalkeeper was rushed to hospital after collapsing during a morning training session.

Casillas remains under observation but is now in a stable condition following surgery, and has tweeted a reassuring message that he is ‘feeling strong’ .

Barcelona put club rivalry aside to tweet their support for their Casillas, and sentiment echoed by Messi in the aftermath of their brutal 3-0 victory over Liverpool.

"Happy with the result of tonight," read Messi’s Instagram post.

Messi and Casillas in action during El Clasico in 2014 Photo: AFP/Getty Images

"But we still have to go to Anfield, a very difficult stadium, where Liverpool – who are a great team – will push hard.

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Contentos con el resultado de esta noche. Pero aún nos queda ir a Anfield, una cancha muy difícil, donde el Liverpool que es un equipazo apretará mucho. Viene el momento más importante de la temporada y hay que estar más juntos y unidos que nunca. Por último, quiero aprovechar para mandarle un abrazo a @ikercasillas y desearle que se recupere muy pronto.

A post shared by Leo Messi (@leomessi) on May 1, 2019 at 3:08pm PDT

"The most important moment of the season is coming and we have to be closer and united than ever.

"Finally I want to take this opportunity to send a hug to Casillas and wish him to recover very soon."