Actually, they WEREN'T among the best in the order. Saessee was a pilot, and Agen was a random jedi master who just barely got appointed to council thanks to the Clone Wars attrition rate.
And it really does Sidious credit to have defeated such valiant foes indeed... Agen was half turned from Sidious when Sidious attacks (I just rewatched the scene) and Saessee apparently can't defend from the chin down. And then every time Mace defends and has an opening, he SITS THERE in the most horrid way possible and doesn't counter attack.