Big fan of Call of Duty: Modern Warfare 3's Spec-Ops mode? Then boy do I have the achievement guide for you. In what looks to be a pretty tough to get achievement to get, 'Serrated Edge' asks of you to take down a Juggernaut with your knife. Luckily, you're allowed to use as many flash grenades and pump him with as much lead as possible, as long as the final blow is with your knife.
Here, let Ray and Mike from Achievement Hunters show you how to do it.