Is it just me or does it look like in that last scan (where there is a profile of Naruto looking back at Pein) Naruto looks like he is smirking. Almost as if he wanted Pein to catch him so he could get within striking distance. It would be brilliant since now there isn't anyone between him and the Pein he wants to defeat (the one that acts as a shield is now holding him from behind).
Just a thought.
No, he's actually talking smugly to Pain and then he's surprised when Pain starts sucking his chakra out.
Sakura's seen him fight a bunch of times. During the Chuunin exam he fought Orochimaru, Neji, Kiba. And in part two his fight with Orochimaru where he popped 4 tails. Just naming those off the top of my head.
BTW F-ing Awesome chapter! I can tell where Kishi gets his Anime/Manga roots from. ^^
The only fight you listed that he was impressive in was was his fight with Neji, and that was at the end of the fight. Also, Sakura didn't see KN vs. Oro.
This is the first time Sakura will see 'Will of Fire Naruto' fight.