In my opinion, the above Dusclops Set is flawed as it attempts to reach beyond it's Movepool and Stats to do a job that it is outclassed by other Ghost at. But Dusclops is not an idea Pokemon to take down Tyranitar much less a Pokemon of the OU Tier. Judging by the Moves, EVs, and description of your Set, I assume your Duskclops was intended to be a Tank, or Bulky Sweeper. In that case, evovle it into a Dusknoir and use this Set, as it is a better Tank than Duskclops.
Dusknoir @ Leftovers
Trait: Pressure
EVs: 252 HP / 252 Atk / 4 Spd
Adamant Nature (+Atk, -SAtk)
- Focus Punch
- Shadow Punch
- Substitute
- Pain Split
A viable Tank Set that is takes advantage of Dusknoir's strenghts Typing and Stat wise. The SubPunch Set is a Set focused around dealing massive Damage with the Base 150 Power'ed Move, Focus Punch, which can be safely launched behind a Substitue. Dusknoir's natural Defensive Stats allow him to stay behind a Sub for a hit or two, while decimating the foe with his awesome Ghost+Fight combination with Shadow Punch as a STAB. Pain Split is a form of Recovery, although unreliable, that brings the foe within KO range. The given EV Spread allows him both the Bulk to sustain a Substitute and the power to unleash major pain with his Ghost+Fighting* Coverage.
