The hosts took the lead just before half-time through Sander van de Streek, leaving Trabzonspor with work to do after the break.
The visitors drew level early in the second half when Onuachu won a penalty and calmly converted past Antalyaspor goalkeeper Julian.
However, the Nigeria international was unable to complete his brace after Trabzonspor were awarded another spot-kick 11 minutes from time, with his effort this time saved.
Despite the miss, Onuachu has now scored 13 league goals this season and is joint top scorer alongside Istanbul Basaksehir’s Eldor Shomurodov.
Trabzonspor remain third in the table with 42 points, four behind leaders Galatasaray.
