Scar shouldn't have won in ANY scenario, and for one simple reason:
Preds see body heat. Xenos don't have body heat.
All the things which Scar did in the fight required him to be able to see the queen. The queen gave off no body heat, and was in an area with subzero temperatures.
Anderson, being the twit he is, forgot this crucial fact, and made Scar able to see the queen when he shouldn't have been.
All things considered, Scar should have been turned into a bloody smear 2 seconds into the fight.