Career
Born in Mendrisio, Ticino, an Italian-speaking canton, Switzerland, Martinelli moved south to Italy to start his professional career. He left the reserve team of University College Sampdoria in 2012 for Calcio Portogruaro Summaga. Martinelli returned to Sampdoria in June 2013.
He signed a new 5-year contract with the Genoese club
On 2 September 2013 he was signed by Venezia. On 7 July 2014 he was signed by Modena in a temporary deal, with a option to purchase.
He left for Brescia in the same formula on 9 July 2015. Martinelli played every game in 2010 Union of European Football Associations European Under-17 Championship.
He also played for Swiss U18 team against Belgium and against Spain.
He also received call-up against Austria and France but did not play. He only played once for Swiss U19 team in competitive match in 2012 Union of European Football Associations European Under-19 Football Championship elite qualification. He received call-up against Northern Ireland (he played once), Finland, (he played twice) Netherlands (once) and Estonia (once) in friendlies.
In October 2013 he received his first U21 call-up.
He made his debut as one of the starting XI.
