The helmet of the murmillo was designed to protect the head of the gladiator. Weighing about four kilograms, it was air-tight, just like an iron can. There was a hole in front of the helmet that allowed the gladiator to look at his surroundings.
Usually, it was hard for the opponent to stick his sword into the observation hole because it was tiny, not to mention that the gladiator would be moving around too.
This required keen observation and precise power control to carry out such a feat. Looking at Zhang Heng's previous fight with Garba, Zhang Heng had not possessed abilities like that just yet. In other words, it was simply a coincidence that Zhang Heng managed to strike his sword into the observation hole.
The referee checked again and confirmed that Zhang Heng's training sword did pierce at Garba's eye first, so he announced that the final winner of the battle was Zhang Heng.