As sort of a follow-up on Neoliminals post....
Step one is to be able to delay their first touchdown for as long as you can. While you are doing that, all your 'spare' players are positioning themselves so that any block with a pushback gets another amazon (or elf, skaven, goblin, skink) into the 'corral'. Somewhere down the line your opponent will get a turnover, meaning you can pound on the poor things left in the corral. And the more you get off the pitch (even if only KO), the better your chances of keeping the entire team locked in.
Basically you form a big cage around all his players, doesn't always work brilliantly, but you should be able to get 5 or 6 of them in there. Though if he's lucky enough to roll only 6'es on dodges.. well.. you were SOL anyway
The same trick works well on your offensive drives too, _if_ you have a good chance of keeping the ball, or are well ahead anyway.