Career
Sekulic made his Association of Tennis Professionals main draw debut at the 2012 If Stockholm Open, partnering Patrik Rosenholm, but they lost in the first round to the top seeds. At the 2013 If Stockholm Open, Sekulic qualified for his home event, defeating Tobias Blomgren, Fred Simonsson and Julian Reister in the qualifying rounds. In the main draw he lost to January-Lennard Struff in the first round in straight sets.