At first Mandarin would look completely out of Shang's league. He's flipping cars over with kicks, karate-chopping thick steel walls in half, just physically waaaaayyyy out of Shang's league, even without his rings.
Shang is frantically doing gymnastics to stay alive, and it just looks like it's a matter of time before Mandarin lands one hit and explode's Shang's entire body into gore.
In his thought-baloons, though, Shang notes that Mandarin uses hardstyle moves almost exclusively, and that his hyperaggressive style uses chi like a jet with the afterburners on uses jet-fuel.
So he'd keep using softstyle and gymnastics until Mandarin ran out of gas. Once Mandarin is completely out of mystic chi, Shang would just go to town on him.
I'd also have Mandarin fight some other guys unarmed to set up how powerful he is. He's decapitate one guy with a single karate-chop. He'd punch at the same moment another guy punches, their fists would meet, and the Mandarin's punch would reduce the other guy's entire forearm to gore. He'd karate-chop an opponent literally in half from shoulder to waist.
Establish that The Mandarin is The Man of Iron: someone whose chi puts him physically on another level so long as that chi lasts. This makes it all the more impressive when Shang's mastery of softstyle redirecting moves runs this seemingly invincible monster out of gas.