Well, there's moist, and then there's tender and they are different deals.
Tenderizing cheaper cuts of beef could be mechanical (beating the crap out of it) temperature/time-treated (low and slow) or chemical.
The latter is special bacteria at work ... rub it with some fresh kiwi pulp for a few minutes if you're worried about it being too tough ... do NOT marinade in kiwi unless you want it dissolving into a wet noodle. 15 minutes max will make it noticeably more squishy. And yeah go easy on the heat.