Really? When did this happen, please post proof because this never happened.
So you're going to pick a random fight? That wasn't even a plan, what about when Shikamaru was lying helpless vs Hidan and would have died not for Kakashi, what about when he failed to catch him in his shadows and was outclassed in every way? What about when Kakuzu shot a lightning blast and Shikamaru could do nothing but stare in terror and wait to die until Kakashi saved him? What about vs Tayuya when she had him pinned down and was about to kill him if not for Temari? What about when Temari's plan outclassed Shika's and he was out of chakra and couldn't continue and was forced to give up? What about when Shikamaru was lying helpless in the face of Gedo Mazo's giant foot until Chouji was forced to save him? What about when Kinkaku casually detached Shika's shadow and proceeded like nothing happened whatsoever and would stomp him if not for the entire division? Where were his "smartest character ever" strategies then? Oh yeah, he didn't have any, he's your average ninja, nothing special.
Way to discredit the actual intelligence Sasuke has pulled off in the past like fooling Danzo after successfully deducing Izanagi and deducing the difference between Deidara's bombs using raiton and leading Itachi right into his trap etc.
Just because Kishi says "this is what a strategy is" doesn't make him the smartest character ever just because the readers are too incompetent to realize when a good strategy actually happens. This paragraph, not necessarily directed at you, just the people who blindly read the manga and consider Shikamaru so unparallelled in intelligence because they can't comprehend strategies unless Kishi screams out.
Really? Because countless time he has shown and disproven Shikamaru as anywhere near "smart" because of ridiculous intelligence other characters show that Shika can never hope to ever compare. Kishi scrapped Shikamaru as considered a genius the second he made it, he's fodder compared to higher level shinobi, this was proven the same chapter he was baselessly called a genius. His strategies are casualyl crapped on by other characters, this is coming from someone who actually payed attention to most of the strats in the manga even though Kishi didn't outright say "hey guise, this is smurt".
Shikamura by every definition of the word is smarter, if the both played shogi he would win, if they both played chess he would win, if the both played checkers he would win, he is a strategic machine.
He would solve every riddle first.
In a battle, where defeating the opponent means to find a weakness that can only be found by strategic assessment and observation of the situation he would win first.
Intelligence of his level is known around NU, he is from a clan famous for intelligence.
As for who would win in a fight, Sasuke probably dominates, that is because of Sasukes raw power.
Give both Sasuke and Shika two days prep time and intel, Sasuke would be a fool to fight him
All of the battles that you mentioned are based upon Sasukes KG, his eyes see things that most can't, intelligence is how he uses that, which yes he has shown, but no it is nowhere near Shikas level.