First encounter: Sasuke and Kinshiki fight on par at an extremely high velocity. When they first start clashing Sasuke gains the lead while Kinshiki trails him. But Kinshiki closes the distance quickly and delivers two powerful attacks that send sasuke flying. They go flying out the building and continue fighting. Sasuke gets a kick in but Kinshiki returns the favor by smashing Sasuke into a boulder. And the weapon that Sasuke tried to throw at Kinshiki? Kinshiki caught it. Before Sasuke could even move Kinshiki smashes him through the boulder. He then follows it up with another attack and smashes Sasuke into a boulder behind the one they were just on. Sasuke literally had to ameno out of the way. Sasuke thinking he is slick, attemps a kunai stab on Kinshiki's neck. But to no surprise Kinshiki flips him over and nearly crushes his body with a powerful punch. Kinshiki then speed blitzes him and Sasuke looks up surprised as if he saw a ghost, Kinshiki hovering over him with an axe. Sasuke BARELY ameno's out of the situation and flees because he knows he was going to die if he kept fighting him. Momoshiki replies with "You're sloppy Kinshiki". Imagine if Kinshiki was trying his hardest.
Second encounter: Kinshiki returns and swings his axe at Sasuke but someone with shadow possession jutsu paralyzes him. Sasuke nearly died.
Third encounter: Once again Sasuke and Kinshiki start battling. They are equal as usual but Sasuke has the help of two kages this time. Luckily Kinshiki is stopped by the kages and sasuke flees off to help the other guys fight Momoshiki. Kinshiki after being enduring 8-9 stab wounds from water boy and paralyzed by the lime jutsu, breaks free, knocks back two kages, and swings his sword which slices the juubi tree down and creates a huge shockwave. And the dudes skin was literally ripped torn off on his left arm
And you're telling me Sasuke could beat him?