Nah, they would be out for blood in this scenario, otherwise the premise of fighting them wouldn’t make any sense. The bigger problem for the tiny horses is their inability to reach the upper parts of your body. Sure, they probably have a mean bite, but because of their size and the shape of their teeth they most likely won’t be able to enclose your leg. A horse bite crushes, so keep your fingers away and you are most likely fine.

They also have hooves, so no scratching and climbing. Horses hooves are dangerous because they have a massive horse behind it when it comes flying towards you. Take that away and they could be baby fist for all you should care.

If you look at their jumping capabilities, yea they ar impressive for an animal of their size, but once you are 30cm tall it’s much less impressive to jump as high as you are tall (and horses really don’t jump all that high, most of it comes from tucking their legs).

If you compare the tiny horse to a cat, the cat would be much more dangerous, because it has claws, sharp teeth and can reach your face. As long as you wear heavy boots and have a good stomping/kicking technique you should be fine versus duck sized horses.