Education
Collarini had represented Argentina in the early days of his career from 2007 to 2010, until he chose to represent United States of America from 2010 to 2012 before switching back to represent Argentina.
Collarini had represented Argentina in the early days of his career from 2007 to 2010, until he chose to represent United States of America from 2010 to 2012 before switching back to represent Argentina.
In 2010, he reached the final of the French Open boys" singles event.
On the junior circuit, Collarini had a career high International Tennis Federation junior ranking of 5 achieved in 2009. Collarini has a career high Association of Tennis Professionals singles ranking of 186 achieved on 9 June 2014. He also has a career high Association of Tennis Professionals doubles ranking of 322 achieved on 4 May 2015. He has won 8 International Tennis Federation singles titles and 6 International Tennis Federation doubles titles. Collarini won his first Association of Tennis Professionals Challenger title at the 2015 Blu-Express.com Tennis Cup in the doubles event partnering Andrés Molteni.