Well Sasuke isn't really holding back, that's actually his fighting style which many fanboys doesn't seem to get (not calling you a fanboy). Sasuke usually starts off in close combat then builds up to his bigger jutsus. He's been doing that since we've seen in at the start of Shippuden for most of his fights depending on the opponent. Sasuke was fighting for the kill, using his fire ball jutsu as a feint to try to chidori Naruto from behind shows that.
Sasuke build his way up with the jutsus he uses. People say he could just use CT but they don't even know the requirement is to use the coreless CT, he used it on chakra beast so probably made their chakra bodies the core which might not be the case fore people so he might have to use the core on people. That's like me assuming Naruto will turn his Kurama avatar into lava like how the 4 tails Jinchuuriki turned his body into which melts any rock that tries to surround him plus those rocs can act as a shield for Naruto who have sensing abilities while Sasuke needs to see Naruto to attack.
All I'm saying is its not going to be easy for either and the fight only started.