their lineup is
dusa
sven
bane
earthshaker
ursa
taking away the fact that i can't play AM, AM was the best pick, right?
Not sure tbh. AM doesn't fare that well against Ursa, Sven and Bane actually. ES has chain stun as well. Honestly, 4 of those 5 heroes are reasonably good against AM. I don't think he's the best pick here.
Slark could've worked as a position 1 but he has problems with Bane and too. How did they lane it? ES off lane?
Sniper could've possibly worked since people at 2k (which was your rating, wasn't it?) are less likely to buy Blinks on cores but that depends on how good your Sniper is. Hero is not exactly mechanically overburdening but doing well with him requires quite a bit of practice these days.
edit: Carry Windrunner, my 6.84 favourite, could've worked. In fact, would have worked better than AM. She has problems with lockdown (who doesn't?) but the enemy carries are all pretty useless against her.
Also, I think Sven is easily one of the toughest match ups for AM. Unless AM is super far ahead (which can quickly happen to be fair), he can't fight him 1on1 until he has a Butterfly and Sven no MKb as a counter measure. In any other case, AM just gotta run. Pretty sure 6 slotted (incl. consumed Moon Shard) Sven kills an equally farmed AM two or three times over before an AM gets Sven's HP to 0. Need to check that out in a lobby though.