Mesprit's Psychic Bind hurts LostGar pretty badly,
How so? PONT, Dex, Drawer, Twins, and Spiritomb all circumvent the Power Lock. LostGar doesn't, and as far as I remember, never has relied on a Setup run to maintain itself.
By the time you give up the lock, they usually don't have enough time to achieve their win condition.
...What? Correlation / Causation fallacy please. Not that I'm trying to defend Lostgar out of some sense of lolfavouritism, but I prefer to see the thinking behind this claim.
If the Gyra plays one mew, it's easy to OHKO gengars.
Srsly? What difference does it matter with Gyara versus Mew? Why don't you run one more Gyara if you're gonna run a Mew Prime?
Gengar wins by getting a better start than g-dos pretty much, now that I think about i'd say gyarados wins this matchup.
Wait, you change your opinion now on Gyarados-Gengar matchup? What, you weren't thinking clearly before?
Getting the psychic bind before the g-dos does is very important, the first mesprit usually wins; though gyarados can keep it going longer.
Again, more pontification. What does Psychic Bind have
anything to do with it? Both decks can run just fine without powers. Explaining is your friend.
By the way, lost zoning one magikarp isn't even that bad. It's still a two hit KO. ALSO, the LostGar I played against did not run Devoluter.
I would argue otherwise. Not OHKO-ing a Pokemon in a deck that runs 4 Seeker is a bad idea, mainly since Gyara runs BTS like mad. Let's say I run 3-4 BTS in a Lostgar deck. Let's say you run 3-4 BTS. That's 8 BTS running about. Seriously? No Seeker, slap down Gastly, Haunter, Gengar Prime, attach and retreat active using Warps / whatevskies and then Hurl?
Also, you need to play against someone with a Devoluter. Get on that hoss.
EDIT: That said, playing against Lostgar with a Gyarados deck just requires a bit more adaptive thinking, that's it. You just make sure you don't have Magikarps on your Bench and if you're still worried, then run a 1-1 DGX line with a Premier Ball or something to shut off catastrophe. Run warps. Done. Make sure you don't have Pokes in your hand, and if they Seeker you, then don't bring up a Magikarp.
If you really are worried, then heck, run 4 Special Darks for Gastly donks and Judge for 4 turns.