^ My bad. And yeah, talking about the accuracy drop and the most probably difference of levels. Tyranitar will need the use of Guard Specs + Maybe a Hyper Potion (if you're having bad luck) to properly overcome Espeon.
Also, I want to suggest this "little" one:
Onix - Mid Tier
- Availability: Earlier and easy, you can trade one for a Bellsprout on Violet City.
- Stats: Low avarage. High physical bulky, horrible special bulky, low attack, decent speed.
- Movepool: Avarage.
Earlier: Rock Throw, Bind, Screech, Mud Slap (TM)
Later: Sandstorm, Dig (TM), Curse (TM), Toxic (TM), Iron Tail (TM), Strength (HM), Rock Slide (Breeding)
And he can learns Earthquake, but you may prefer to use the TM on other Pokémon with better attack.
- Utility: He's better than Geodude before it evolves, and is somewhat similar to Graveler, except because Onix prefer to deal damage with Bind + Sandstorm and wall the enemy while he's Screeching it for others or himself, too. Also, he can handle and survive to any random Self-Destruct and Explosion, and give you time for revive/heal him's partners on mid battle. He will not sweep any time soon, but he can easy handle a good number of trainers and gyms alone. Also, he's a in-game trade, so, he'll win experience faster and will have better levels with less effort, and if trades are counting, Steelix is just awesome.
- Match-Ups:
Falkner: Onix wins alone; may need a Potion if you're missing too much.
Bugsy: Onix wins alone; may need an Antidote because Kakuna.
Whitney: Onix wins alone; Cleafairy can be a trouble because Metronome.
Morty: Can be of help if he knows Dig or Mud-Slap, because he only fears Night Shade and Gengar.
Chuck: Can use Screech on Primeape and deal some damage, but he can't do nothing against Poliwrath.
Jasmine: Can handle without trouble the two Magnemites, and Mud-Slap a while her Steelix.
Pryce: Useless.
Clair: Can handle the second Dragonair, but is useless against the others two and Dragonite.
Will: Useless.
Koga: Useless against Ariados, but wins to Muk, Crobat, and Forretress, and can help against Venomoth.
Bruno: Can handle Hitmontop and mirror Onix, but is useless against the others.
Karen: Wins against Umbreon, Murkrow, and Gengar, and have high odds against Houndoom, but is useless against Vileplume.
Lance: Wins against Aerodactyl, and can handle at some degree Charizard, but is useless against the others.
Brock: Can mirror him's Onix, otherwise useless.
Misty: Useless.
Lt. Surge: Onix wins alone like a god; may need a Hyper Potion for the Explosions.
Erika: Useless.
Janine: May need Antidotes and a Hyper Potion, but can handle the gym complete bar Ariados.
Sabrina: Useless.
Blaine: Wins against Magcargo, and have high odds against Magmar. Can be of help against Rapidash, but he can't beat him.
Blue: Wins against Pidgeot, but is useless against the others.
Red: Wins against Pikachu and Snorlax, and can handle well him's Charizard. Useless against the others.
Additional Comment: He's great to leave wild Pokémon with almost 1HP, because him's low attack.
Note: The Match-Ups and Tier are considering he's not evolving, otherwise he's Top Tier.