Incheon suffered its third defeat since returning to the K1 League today, losing 3:1 at home to Daejeon.
The guests took the lead in the ninth minute through Masatoshi Ishida.
Mugoša equalized in the 36th minute, and Tejžon then went on to score with goals from Diogo Oliveira in the 85th minute and Um Woona-Sang in the 94th minute.
After four rounds, Inchon shares last place in the standings with Jeju with one point each.
Mugoša is on coach Mirko Vučinić's list for the upcoming friendly matches with Andorra and Slovenia in Podgorica.