I've never been able to do this but if you know please answer.

Shang Tsung has the Soul Steal ability, which takes health from your opponent and gives you health. But if you were to get damaged, and use the Soul Steal to get back to full health, and win, would this be a flawless victory?

If you know please answer. If you don't know I encourage you to try it and let me know. I'm still trying to see if this works but am having no luck.

No, it wont work as you initially took damage. Flawless Victory is taking no damage, period.

Curious, are you trying to go for the Flawless Victory achievement online? I recently started playing this game again, went into the chat lobby match, got into a game and asked the guy if I could get a quick flawless victory (only requires one round). He was up for it, then we had our matches/rematches after that.

No, not online. I was curious about it though. I started playing this game no longer than 2 weeks ago.

Thanks. Now I know that this won't work. But I have almost got the achievement