The Sasuke Recovery arc was a Naruto storyline that occurred shortly after the Chunin Exams. The events of its trials made the young Uchiha become deeply dissatisfied with his training under Kakashi and of Konoha in general -- a fact that Orochimaru himself would carefully orchestrate.
As he prepared to leave the village, Naruto and his allies would chase after him in hopes of recovering their friend before being delivered into the fallen Sannin's hands. Consequently, a number of skirmishes broke out between the heroes and Orochimaru's lieutenants, culminating in an epic battle between Naruto and Sasuke himself. By ranking the power of the individuals involved, we can appreciate the strongest shinobi of the arc.
10 Choji
Choji's performance in the Chunin Exams may have been one of the most underwhelming and lopsided matches of the first round, though he compensated for his defeat during his battle against Jirobo. He was the ninja to defeat a member of the Sound Four without assistance.
During their battle, he would demonstrate the full capacity of his techniques, including partial expansions, super expansions, his butterfly form (which augments his body beyond the power of Jirobo's curse mark), and his spiking human boulder. Such a diverse arsenal makes him a considerable threat in melee combat.
9 Shikamaru
Despite Naruto's close relationship with Sasuke, Shikamaru's genius was responsible for conducting the operation - a fact that even the knucklehead ninja himself conceded was a sound idea. Though his shadow possession jutsu lacks firepower, it becomes a deadly threat to any caught under its sway.
While Nara would require Temari's assistance to defeat Tayuya, he had also defeated the sand sibling in the past. This entails that none of the three are specifically weaker than one another -- instead, their jutsu merely counters under specific circumstances.
8 Neji
Neji was the only other ninja to have defeated a Sound Four agent through his own merits, overcoming Kidomaru in spite of the fact that his jutsu technically countered Hyuga's own. He accomplished this through fortitude, tenacity, and sacrifice to his personal safety.
Not only were Neji's skills demonstrated through the battle against his Sound shinobi adversary, but he also excelled in the Chunin Exams, nearly defeating Naruto Uzumaki (and would have, were it not for the knucklehead ninja's resourcefulness). He can unleash a flurry of targeted jabs through his palm technique, rendering him a formidable melee opponent.
7 Kankuro
Kankuro's puppet mastery is second only to Sasori's himself. He intervened on Kiba's behalf during the hound shinobi's fight against Sakon and Ukon, concluding the fight shortly after he arrived in the hero's favor.
His puppets are outfitted with a number of deadly weapons, including noxious gases, poison-tipped blades, and even the ability to entomb his adversaries in a makeshift doll coffin. The latter technique is referred to as "the puppet show," a skill he would use to safely dispatch his Sound ninja opponent.
6 Temari
The sister to Gaara, Temari's legendary skills with her fan and wind jutsu surpass even that of Kankuro's puppets. She assisted Shikamaru in his battle against Tayuya, and her skills had clearly improved since their fateful match during the Chunin Exam.
Specifically, a single gust of her fan was capable of cleaving through the boughs of trees, expediently dispatching her Sound ninja opposition in the process. Temari's combination of range, experience, and caliber render her one of the Leaf's deadliest allies. Were it not for her intervention, Nara may have died in his battle.
5 Rock Lee
Rock Lee intervened on Naruto's behalf during his battle against Kimimaro. Despite being recently hospitalized, he was fully prepared to defeat the bone using villain, relying on his "medicine" (most frequently known as alcohol) in order to vex him with a new martial style primarily oriented on dodging.
Lee's taijutsu skills are so unrivaled that he can move as a blur, penetrating Gaara's defenses and being the first ninja ever to have landed a direct blow against him. Further, his lotus ability can cause enough unbridled devastation to crack large swathes of solid stone.
4 Kimimaro
Perhaps Orochimaru's most powerful soldier short only of Kabuto, Kimimaro's Kekki Genkai allows him to protrude bones from any orifice of his body and use them as weapons. Each was as hard and sharp as steel, durable enough to defend against the brutal force of Rock Lee's kicks.
When backed into a corner, he is also capable of creating a bone graveyard, one that would have skewered Gaara and Lee simultaneously if not for the former's ability to fly. Though he may no longer be an official member of the Sound Four, Kimimaro was easily the strongest.
3 Gaara
Until recently, Gaara had been known only as the murderous monster of the Sand village. However, after his defeat against Naruto Uzumaki, he demonstrated his capability of putting his frightening powers to a good cause.
His "Sand Coffin" jutsu is extremely difficult to escape from, cocooning his opposition within his grainy particles and tightening their restraints until it crushes the life from their body. Further, his defense is also commendable; the Kazekage may deceive opponents through sand clones or use his jutsu in order to create an impervious shield that encompasses his entire form.
2 Naruto Uzumaki
The Nine Tails Jinchuriki, Naruto Uzumaki's power had not yet reached its potential during his first fight against Sasuke in the Valley of the End. Though he could tap into Kurama's chakra and use it to aid in his battle, he would become feral and undisciplined by doing so, losing the intelligence and savvy that granted him victory over Neji Hyuga.
Nonetheless, he was nearly able to defeat Sasuke and even forced him to unlock the power of the curse mark in order to fend off his former friend's furious flurry of attacks.
1 Sasuke Uchiha
Poetically, the subject of the arc would also be its strongest active combatant. Through the power of the curse mark and the mastery over his sharingan, Sasuke could track Naruto's obscenely swift movements and counter them. It would be imperative to his success and give him a distinct advantage.
Learning the chidori was also an excellent utility in defeating his teammate, with his jutsu augmented through Orochimaru's "gift." When synthesized with his existing abilities (such as his formidable and frequently underrated fire style), he was one of the few characters to have bested Naruto -- even if his victory would be too narrow for his liking.