Team GB's Martin Stamper has lost in the men's -68kg taekwondo semi-final.
The first round of the contest proved key as Tazegul opened up a five-point lead.
Stamper responded by winning the second 2-1, but he remained four points behind heading into the final round.
The Brit rallied to reduce the score to 6-4, but Tazegul responded with three successive scores to eventually win the fight 9-6.
The Team GB competitor will now fight for a bronze medal later this evening.