I'm sure most of you don't care, but I've just started playing about 2 weeks ago and got my first 12 win run in arena today!
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One loss was my own disconnect.
In my excitement, forgot to take a 2nd screenshot to get entire decklist, but the notable ones are: 3 flamestrikes, 2 faceless summoners, boulderfist ogre, corrupted seer and a fossilized devilsaur. I'm sure I'm forgetting something else, but those were the big cards.
I thought my weak early game would bite me in the ass, but I was always able to hold on enough until my mid/late game cards took over. 3 flamestrikes is clearly ridiculous, and I had a few spots where I'd sort of 'blow' the first one on just 2 creatures to bait them into going wide after and then hit them with the 2nd one in my hand :-D.
I even cast a total of 4 flamestrikes (thx ethereal conjurer) in one game, felt bad for my opponent.
The craziest game though, by far, was one at 10 wins against another mage. He had duplicate secret, killed his servant of yogg and cleared the board. The first copy he cast did elemental destruction and cleared the 2 minions he had out (I had none). The 2nd one cast naturalize when his servant was only minion out, so he killed it and I drew 2. That was definitely the turning point of that game and shows why I really dislike that card. Even if one of them had stuck, I still think I was in a decent spot to win the game, had a flamestrike in hand when he did all that, that I never ended up using.
edit: oh, and since that run, I've had 7, 9 and 8 win runs. They weren't all insane like this one, so I think I'm starting to get into a much better spot with regards to arena. My previous best before today was only 7 wins, and I was averaging in the 3-4 range.