 At international level, Zárate scored the winning goal as the Argentina under-20 team won the 2007 FIFA U-20 World Cup final.Zárate began his club football career at Vélez Sarsfield where he had played since childhood.At age 17, considered too strong for the youth category, he was promoted to the first team with which he made his full debut on 21 April 2004 against Arsenal de Sarandí.