Signed by Internazionale along with Rene Krhin at the age of 16, Belec spent 3½ seasons with F.C. Internazionale Milano Primavera team. In the first season he was a backup for Paolo Tornaghi and won the Primavera Scudetto that season. He also played for Campionato Nazionale Allievi under-17 youth team in 2006–07 season. In 2007–08 season, at first he had to compete with Enrico Alfonso for the starting place in Primavera team until Alfonso left the club in January 2008. He then became the fourth keeper of Inter's first team. and as the first choice in Primavera, which won 2008 Torneo di Viareggio with team and finished as the league runner-up. Under José Mourinho, Belec received several first team call-up since 2008–09 season and made his first team debut on 17 July 2009, on a pre-season friendly. He also played at World Football Challenge. In November 2009, he signed a reported five-year contract with the club.
On 6 July 2010, Belec completed a loan to Serie B club Crotone. He made his debut on 5 September 2010 after Emanuele Concetti was not available. He then became the first choice goalkeeper ahead of Concetti since round 18. However, in 2011–12 Serie B, his former Inter "team-mate" Giacomo Bindi took the starting place from round 2 to 4 and again since round 9, made Belec becoming the understudy. However, after a 0–3 defeat to Brescia, Belec re-took the starting place. Despite Leonardo Menichini was sacked again on 23 January and replaced by caretaker Massimo Drago, Belec remained as the starting keeper of Drago's squad.
Return to Internazionale
Belec returned to Inter during the summer 2012 window after his loan deal to Crotone expired. He was kept as a third choice keeper behind Samir Handanović and Luca Castellazzi. He made his first team debut on 30 August as a substitute in a UEFA Europa League game against FC Vaslui to replace Antonio Cassano after starting goalkeeper Castellazzi was sent off.
On 1 September 2014, Belec was signed by Konyaspor in a temporary deal. On 2 February 2015 the loan was terminated.
Carpi
In summer 2015, Belec terminated his contract with Internazionale. On 31 August 2015, he signed with Carpi F.C. 1909 for one season. He made his debut in Serie A in a win against Torino on 10 October 2015. After debut he became a regular starter in first eleven for Carpi. On 30 May 2016, he signed a new two-year deal with Carpi.
