You mean he was mad it was the mirror? What even happens in a Dredge mirror? Is is just who goes off better?
No, he was just salty about how hard it is to win Games 1-2. But you play your own hate; just not symmetrical hate. Leyline of the Void is a good card for a Dredge player even outside of the mirror because it prevents oppoenents players from bolting their own Delvers to exile your Bridge from Belows. Tormod's Crypt is also good as is Ravenous Trap.
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(For the uninitiated, here's the quick n dirty AG Vintage Dredge primer)
Sample Deck said:
LANDS
4 Undiscovered Paradise
4 Bazaar of Baghdad
4 City of Brass (Ed: I use Mana Confluence so I don't have to stack more triggers)
4 Dakmor Salvage (Petrified Field acceptable; expensive. Dredge 3)
25 CREATURES
4 Golgari Grave-Troll (Dredge 6)
4 Bloodghast (Landfall: Return to play from GY to Battlefield)
4 Stinkweed Imp (Dredge 5)
4 Narcomoeba (When put into GY from library, put into play)
3 Ichorid (During upkeep, may exile black creature from GY to put into play. Sac at end of turn)
1 Flame-Kin Zealot (Gives all creatures haste and +1/+1)
1 Sun Titan (return card with CMC 3 or less to play when ETB or attack)
2 Golgari Thug (Dredge 4)
INSTANTS and SORC.
4 Cabal Therapy (name a card, opponent discards all cards of that name. Flashback - Sac a creature)
4 Mental Misstep (1 blue Phyrexian Mana - counter a 1CMC spell.)
2 Darkblast (Target gets -2/-1; dredge 2)
4 Dread Return (Flashback - Sac 3 creatures - return creature from GY to play)
8 OTHER SPELLS
4 Bridge from Below
4 Serum Powder
You mulligan any hand that does not contain Bazaar of Baghdad. If your hand contains Serum Powder and not Bazaar of Baghdad, exile your hand to get more shots at Bazaar of Baghdad.
Put cards with Dredge and Bridge from Below into the GY. Start dredging through your whole deck on Turn 2. Assuming you played a land next turn (either from your hand or you dredged Dakmor Salvage), you will likely put a Bloodghast into play, or a Narcomoeba from the dredging or you can exile a Thug/Imp to pull an Ichorid into play. Sac the Bloodghasts and/or Narcomoeba to Cabal Therapy naming Force of Will which puts Zombies in play as a side effect of the sacrifice from Bridge from Below. Your Ichorids die on their own to make more zombies, but you can also sac them for Cabal Therapy or Dread Return.
The deck is literally the best deck in Magic unhated. It is very hard to lose game one, even to broken Vintage decks unless they happen to go-off on Storm or Vault-Key on Turns 1 or 2.
The problem is that Game 2 is when your opponent sides in hate in the form of Leyline of the Void, Rest in Peach, Grafdigger's Cage, etc. The Dredge gameplan in game 2/3 is to side out virtually every unnecessary card (e.g. Sun Titan, Fatesticher, etc.) and side in massive numbers of Chain of Vapor, Nature's Claim, and my ultimate favorite, Serenity)
WOTC is giving out copies of the Power Nine to the top 3 players in the Holiday Vintage tourny who don't run the Power 9, but then added Bazaar to that list to stop people like me from just entering with Dredge because Bazaar is a one card combo. Bazaar is just that good - it is almost literally a one card combo by itself. Legacy Dredge is a fringe deck, yet the only important card (meaning Mental Misstep can be discounted) in this deck that isn't legal in Legacy is Bazaar of Baghdad.