About a year ago my friend asked me who wins "the style" battle between GSP and Spider Silva and I said that if any style will ever beat Spider it's GSP's. Sonnen proved my point today. Spider is weakest on his back and he can be taken down. It should be obvious but strikers do not have an advantage over take down artists, it's rock against paper.
While some may not appreciate the ground game, those that know MMA realize that ground work is the reality of fighting. It's the ultimate equalizer because it takes a mans athleticism and accuracy off the table. Suddenly technical perfection, heart, and stamina mean more than all the speed in the world. A GSP take down will rob you of your speed and stamina. A Brock can will shatter your confidence and allow panic to seep in. The ground fighters in the UFC are hard to beat because once they have you, you're basically screwed.
Spider did prove one thing today, that no matter how long you pound on him and force him to work.... he only needs a tiny mistake to end a fight from any position. When opportunity knocks Spider is standing behind it with a handkerchief soaked in chloroform.