Erm - I've just had a rethink too! Not only is Thiem a very good player, but he seems to have a cool head and nerves of steel, and that's going to be important against Nadal, who I can see getting rattled if things don't go his way. Still think Nadal will win out in the end though because his greater experience will probably see him through.
It's going to be interesting Aileen, I hope he really pushes Nadal , if he can't squeak a win