Goztepe stunned the home supporters when Novatus Miroshi opened the scoring in the 16th minute. Galatasaray responded through Davinson Sanchez, who equalised in the 33rd minute.
The hosts completed their comeback five minutes before the hour mark, with Gabriel Sara finishing after being teed up by Osimhen.
The Nigeria international then extended Galatasaray’s advantage from the penalty spot in the 63rd minute.
Goztepe quickly pulled one back through Juan two minutes later, but Galatasaray held firm to secure all three points.
Osimhen has now scored five goals in three league appearances this season, underlining his impressive start.
