This matchup was all about flying. There were lots of creatures to gum up the ground, flying (or mana screw) was the way every game was decided.
(I played RB)
Note: a player on reddit suggested we change the Green Devotion decklist to a version with Genesis Hydra and Nissa. So we did. But we didn’t like this new version, See the Unwritten and Surrak would’ve been better, in this matchup at least.
G1
In the early game, Green ramped up mana and I tried to apply pressure. An early doomfall revealed a Whisperwood and Dragonlord Atarka. I chose to exile the Whisperwood, which was probably a mistake in retrospect, but I thought I could keep him off 7 mana. Sure enough, he gets to 7 mana and plays Atarka. But I have a Phoenix, and I attack into his Atarka. He’s low on life and knows he can’t race, so he blocks, and I use a Chainwhirler and an Abrade to finish off the Atarka. After that the path is clear, a Heart of Kiran and Phoenix kill him quickly after that. RB 1-0.

G2
Green ramps up with elves and rattleclaw mystics. I cast doomfall and this time I steal an Atarka from his hand. He plays Whisperwood. Chandra kills the Whisperwood. He gets Courser of Kruphix. He’s able to kill Chandra. I cast Kari and Scrapheap Scrounger. Later my Chainwhirler kills two rattleclaws. He plays Xenagos and starts making satyrs. He loses his courser and satyr protecting Xenagos from attacks. Courser #2 reveals Atarka on the top of the library, uh-oh. I get an exerted Glorybringer which kills his Xenagos and his Courser. Note that Glorybringer can’t hurt dragons when it exerts! Not that that’s relevant, though, because Atarka will just kill the Glorybringer when it ETB’s. Anyway, my Chainwhirler finally hit his life total directly (during the Glorybringer vs Xenagos attack) so he’s at 17 now. He draws the Atarka but can’t play it yet. Genesis Hydra comes in as a 4/4 and adds a Courser of Kruphix. I sit back and just ping him with Chandra for 2. Then he gets Atarka out, kills the Glorybringer. All I can do is ping him again. Atarka kills Chandra. I draw nothing. Atarka starts attacking me. I get Hazoret but it’s too late, I die to more Atarka attacks. Green Devotion 1-1.

G3 (bad mulligan decision?)
I keep a risky 2-land hand and never see a third. He gets a turn 3 Polukranos and I have useless spells that deal 4 damage, grrr. I can’t do anything. He runs me over with Polukranos. Devotion 2-1.

G4
Green mulligans to 6 cards. (we are still using the old scry mulligan for rest of tournament)
I keep another 2-land hand, but this time it works out. T2 Heart of Kiran follwed up by T3 Chainwhirler to kill a mana dork and crew the ship. He gets Courser. I use doomfall to make him sacrifice the Courser. Ship attacks again. He gets Polukranos. Spyglass from the sideboard naming Polukranos to stop any hydra-fighting allows me to then play Pia Nalaar. I sacrifice a thopter to prevent Polukranos from blocking and force mana dorks to block Chinwhirler, as the ship also attacks again. He buys time with Nylea from the sideboard, gaining 6 life, but he can’t find anyway to stop the flying ship and loses two turns later. All tied up, 2-2.

G5
He gets turn 3 Polukranos on the play, yikes. I kill a Caryatid, and use two spells to kill Polukranos. He has Courser. At 12 life, I find Chainwhirler and kill an elf with it, but he drops land #7 and plays Atarka. I get 2 phoenixes out which could’ve been great, but Courser reveals another Atarka in my future so I am screwed. Instead of double blocking with the phoenixes (which would kill Atarka #1 only to have Atarka #2 played post combat, killing the Phoenix’s “ashes”) I try to buy time with single blocks, taking trample damage and getting back phoenixes during my upkeep, but then he gets Arbor Colossus from the sideboard to kill a Phoenix “ash” and I am out of plays. G Devotion 3-2.

There was a recent question on reddit asking which red decks are the best on history. Well, last tournament I didn’t have much success with Ramunap Red and this time I didn’t with the black splash version of Chainwhirler either. But that Red Prowess deck from 2015 just keeps on crushing its matches. It’s probably the best red deck of all time, I think. One could make the case, in this context, at least.