Is it that unlikely they found one of the hundreds of Anubis-enhanced Motherships that's in the galaxy? Especially since the free jaffa republic got destroyed by the Ori?
I recall those going toe to toe with the Asgard.
True, one of those did destroy Thor's ship, but Anubis himself didn't feel confident enough at the end of that very episode to go up against O'Neill class ships. Presumably Earth ships now have firepower comparable to the O'Neill class, they can make short work of Ori warships and Wraith hiveships. Yeah, I guess it's possible one of the motherships got the jump on the Hammond and knocked the Asgard weapons offline with a lucky shot, but I hate the fact that that's always so easy to accomplish.