Who did you beat challenge 300 with?

I've had the game for months, and I recently got to challenge 300 a couple of weeks ago. I'm very good at the game I'm struggling majorly though I came close a couple time with Raiden and Stryker, anyone got any tips or advice cuz except for DLC (I DON'T HAVE IT YET) though I've used every character.
I don't understand how all of you could beat it in less than 4 tries. It took me like 5 or 6. Oh well, Stryker got the job done.
I did it with Kitana. I dunno why, I just couldn't do it with Kung Lao. Actually, I only beat it this time with Kitana, and then never again, not even with Kitana.
Same here Critical, I beat it with Rain after so many damn tries cause I never got an inch of health back :mad: