That's a crazy strategy from them on the 3rd game. Mid troll and carry Anti-Mage.
It's not a crazy strategy because Troll and AM are a common picks in pub games, maybe the Troll pick was unusual but AM as a carry isn't that crazy, I think that it is actually a good one because Troll can tank the hits and as a Midlaner can help in terms of objectives which AM alone can't do in a pro DOTA scene.