IMO Reptile was the physically strongest and fastest of the ninjas. At the beginning of the fight he was tossing Liu Kang around real good and also landing attacks faster. But he still lost to Liu in a straight up fist fight.
The other two ninjas, Scorpion and Sub-Zero were still overall more powerful than Reptile. Against Sub-Zero Liu had to use unblockable stage interactibles to win. Without those he would have lost convincingly, since Sub-Zeros cold field was a big threat and was spreading fast. Someone like Reptile, who would have the physical advantage against Sub-Zero would still not have an answer for the cold field. And since Reptile was kinda portrayed more primal and animalistic, there is no way he would have pressed R1 during the fight.
And then there is Scorpion. IMO he was the most powerful ninja by far. He lost to Johnny Cage, which isn't really that big of a shame, considering that Johnny beat Goro, who was supposed to be a big deal. And again, stage interactibles were used to defeat Scorpion. Where Reptile lost to regular attacks.
But with that being said, also keep in mind that Scorpion never died. He returned in the sequel, was just about to defeat Sub-Zero, but then kidnapped Kitana instead. So Scorpion could teleport, shoot sentient worm-zipline-creatures out of his palm, spit fire out of his mouth and reform from being blown into 20 mt this breakdown of the fight is legendary bro....... You said he pressed r1 for stage interaction thats ublockable