serra's win was a bigger upset, imo.
I knew TJ had the potential to give Barao a lot of trouble just because he was more athletic. I still thought barao would KO him, but I recognized TJ's athleticism as a distinct advantage (his only advantage, and I thought it would show in the wrestling and perhaps footwork. I never thought he would outstrike barao).
I gave serra literally no advantages in his fight with GSP. I thought serra might've had a better chin, but I could never tell. serra had only been finished once, and he was barely out. he was very fatigued and was caught with a wild spinning back fist, so I sorta gave him a pass. gsp had not been finished with strikes at the time.
I thought serra had the better bjj, but he was too short to make anything happen, especially in an mma fight. I figured it might only help serra never letting gsp mount him. I remember thinking gsp's top game would get the better of matt, with elbows and movement.
at the time, serra had never finished ANYBODY with strikes. his striking was just starting to come together. he rocked karo 2 years prior, but his striking didn't really look too special on TUF 4. it was the biggest mismatch I had ever seen in a title fight (arlovski/eilers might've been worse, I guess). and after watching that fight maybe 100 times, I am just so impressed with serra's performance. he came in ready to bang and looked great. it wasn't such a lucky shot; he fought gsp very very well right from the opening bell.