Hinata, already in the depths of a Heroic BSoD over her surrender against Neji in the Chuunin Exam preliminaries, takes on and defeats a gang of thugs led by a renegade Iwa chuunin single-handedly, motivated by Naruto's faith in her. It's not even a close fight either, not one of them even lays a hand on her until the leader catches her with a paralyzing smoke bomb, which Hinata then fights off the effects of with sheer force of will to take him out with one devastating shot.
Wabisuke's plan to capture Kakashi was brilliant in its execution, forcing Kakashi to expend his strength fighting one of Wabisuke's clones until he backed right onto the blade of Wabisuke's poisoned dagger without even realising that Wabisuke (disguised as Kakashi's client) was an enemy.
Bonus points to Sakura for having the perceptiveness to see through the plan at the last second, even if it was too late.
Naruto's furious defiance of Wabisuke in chapters 4 and 5, refusing to give an inch even as he's tortured horribly for days. There's a reason chapter 5 is called "the Song of Defiance".
It starts with Sakura detonating 36 explosive tags simultaneously, throwing the town into chaos. Keiji opens up with a non-stop barrage of shuriken from such a long range that the Iwa-nin think they're under attack by a much larger force, while Sakura uses the commotion to try and free Kakashi and Naruto.
Naruto and Sakura go 2-on-1 against a highly skilled Iwa chuunin while Naruto's hands are still shackled behind his back. He calls for Sakura to throw him a kunai, which he catches in his teeth to fight.
At the darkest hour, Naruto makes a deal with the Kyuubi for power, shreds his way out of his shackles and dominates Wabisuke, No Selling every attack he makes and tearing off his hand.
Kakashi: It's not smart to leave unfinished business.
In chapter 9, Orochimaru himself catches Naruto, Sakura, Hinata, Hanabi and Temari as they're about to escape the Sound base. When Naruto's attempt to make him back down by threatening him with the Kyuubi don't succeed, he makes good on his threat and orders Sakura to take the others and get away while he holds Orochimaru off. He puts up a stunning fight, even making Orochimaru feel fear before inevitably falling to the legendary ninja, Defiant to the End.
Hinata, who snuck back because she couldn't abandon Naruto, overcomes her fear to leap down to attack Orochimaru to protect a helpless Naruto from him. Keep in mind this isn't the post-Time Skip Hinata who did a similar thing against Pain, this is 12-year old Hinata. Fortunately, Kakashi intervenes so she can get him to safety instead.
Finally, while Kakashi takes Naruto's place at holding Orochimaru off, he's eventually pinned by one of Orochimaru's snakes. All seems lost, when shuriken thrown by Keiji (who turned back as well) kill the snake and free Kakashi. Kakashi uses his Sharingan to paralyse Orochimaru for just the briefest of moments, long enough for Keiji's Deathwind shuriken to cut Orochimaru in half- he survives by dispersing his mangled body into a swarm of small snakes and escaping, but it's too late to prevent Kakashi from joining his team in getting away to safety.
At the end of the long, epic battle between Naruto and Gaara things are looking as bad as they can get as the Kyuubi has suppressed Naruto's consciousness and taken control of his body. But when Hinata's voice is able to reach him, he stands up to it and, when all seems lost, remembers the Five Elements Restrained Seal Jiraiya placed on him]and activates it, instantly shutting the Kyuubi down.
Naruto: What am I doing? Stupid fox, I'm showing you who the one who's really in command of my body is! I'm Uzumaki Naruto, the one who's going to become Hokage and I...
Naruto: ...will not lose to you! FIVE ELEMENTS RESTRAINED SEAL - ACTIVATE!
Naruto versus Tsunade in Chapter 12. Without be able (or willing) to use the Kyuubi's power, Naruto is no match at all for the member of the legendary sannin and Tsunade brutally beats the stupid out of him. But he simply refuses to give up, eventually managing to win (by forcing Tsunade to use both hands, as she'd said she wouldn't) through a combination of cunning and a half-completed Rasengan.
