Pasarell was a prestigious junior and first appeared on the cover of "World Tennis Magazine" at the age of 11 in 1955. He won over half dozen Orange Bowl titles and five US junior titles including the US juniors in singles and doubles with Clark Graebner in 1961. He first appeared in the U.S. Championships at Forest Hills in 1960 and was first ranked nationally that year. In 1962, he played at the Caribe Hilton Championships in San Juan, Puerto Rico. This was arguably the biggest tournament in the whole of Central, Caribbean and South America.