Ranks
Kakashi was jounin at 9 when part1 Sasuke was confirmed chunin lvl ninja by Genma, but not above
Combat aptitude
While 2tomoe Sharingan Sasuke got owned by Lee
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Kid Kakashi was already defeating Lee's master(Guy)
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Difference in speed
Sasuke was keeping up with chunin lvl fighters when Kakashi was already fighting on par with war arcs high speed elite ninjas
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And even war elite ninjas were shocked by his speed
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Sensing
Kakashi also displayed great awareness of his surroundings due to his incredible sense of smell, capable to localise even hiding opponents, impressing even his sensei
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Can't say the same concerning Sasuke who got surprised multiple times by hiding opponents [
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Jutsu execution
Part1 Sasuke couldn't form Chidori without preparations
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When Kakashi could form the handseals and use it on a run in a taijutsu battle against a high speed taijutsu elite ninja before the tip of the blade even touched the ground
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Conclusion
Kid Kakashi was on a lvl above part1 Sasuke and i didn't even take his 2tomoes Sharingan in consideration