Ranking:
D-rank (low Genin - mid Genin):
Kiba — Part 1: Naruto fight
Shikamaru — Part 1: Temari fight
C-rank (high Genin - mid Chunin):
Sasuke — Part 1: Early Chunin Exams
Rock Lee — Part 1: No weights
Neji — Part 1: Naruto fight
B-rank (high Chunin - low Jonin):
Rock Lee — Part 1: Eight Gates
Haku — Part 1: Wave Arc
Gaara — Part 1: Sasuke Fight
Naruto — Part 1: Valley of End
Sasuke — Part 1: Valley of End
Asuma — Part 1 & 2 (pretty much his whole life, lol)
A-rank (mid Jonin - high Jonin):
Zabuza — Part 1: Wave Arc
Kakashi — Part 1: Wave Arc
Might Gai — One through Fifth Gates
Guren — Filler Character
Kimmimaru — Full Power
Yamato — Wood Release
S-rank (low Kage - mid Kage):
Sasori — Part 2: Sakura fight
Kakazu — Part 2: Naruto fight
Tsunade — Part 2: Final fight
Orochimaru — Part 2: No reanimation jutsu
Kisame — Part 2: Killer Bee Fight
Killer Bee — Part 2: Kisame Fight
Itachi — Part 2: Not Edo
Jiraiya — Part 2: Nagato fight
Minato — Kage tenure
Six Paths of Pain — Invasion
Prime A (Third Raikage) — Lightning Armour
Kabuto — Part 2: Itachi fight (pinnacle of this tier)
S-rank (high Kage - peak Kage):
Tobirama — Hard to rank cause of his jutsus
Prime Hiruzen — Said to be the God of Shinobi (he can be higher or way lower)
Prime Onoki — All manga abilities
Prime Hanzo — Feats and Statements are insane; he might be lower, but I like him, so he's here, lol
Obito — with Rinnegan, pre-Ten-Tails Jinchuriki (pinnacle of this tier)
SS-rank (Beyond Kage):
Minato — Nine Tails Jinchuriki
SSS-rank (Strongest in the Verse, excluding Gods):
Madara Hashirama — Can beat everyone else with relative ease