The Japanese and many Asians are of much shorter stature, but none here could claim to hold their own against a ninja or trained warrior.
The Vietnamese held their own against several 1st world armies. (in general and by numerical sacrifice.)
The Mongols rode miniature horses and they did not fair poorly in their conquests.
The ancient Romans were usually of stouter nature vs. the Kelts/Gauls/Germanics, and using shorter swords as well, but in the
https://en.wikipedia.org/wiki/Battle_of_Watling_Street the numbers were said to have been 80k vs 400 and a decisive victory.