Barcelona assistant coach Jon Aspiazu says they must heed the lessons from Real Madrid's shock defeat to Ajax.

Aspiazu gave his opinion on Real Madrid's 4-1 loss on Tuesday, a result which saw the title holders knocked out of the Champions League at the Bernabeu.

He said that "it seemed as if Madrid had the tie under control [after winning the first leg]," but that didn't prove the case in the end. In that sense, he added that "Ajax played a great game, they were on top and they gave us a surprise."

However, he quickly added that "not everyone" was surprised by the KO, but perhaps "by the convincing nature" in which it came in the end.

Aspiazu is clear that Madrid's early European exit should serve as a "warning for everyone because you can relax against anyone, you have to give everything against every team."