Rin Tohsaka is a skilled magic user whose gems can damage even the strongest of opponents. That being said, she would be thoroughly outclassed in a one on one fight against Korra if she didn’t have her servant fighter at the ready. Much like a Digimon partner or a Netnavi, characters from the Fate series typically have a legendary hero as their support. Rin got Archer in the original Fate Stay Night anime and he is quite formidable. His raw speed and power will be enough to overwhelm Korra despite her mastery over just about every element. Speed can definitely play a key role in a fight and as far as this one goes, it was certainly all that he needed, although he won’t get the credit for this victory. Rin Tohsaka wins.