Strategy

Russ was the stronger of the two by a fraction, powering Krakenmaw with the greater heft and momentum, but the Lion had the superior dexterity, angling his parries and thrust to catch Russ off balance. They hacked and drew at one another, circling, feinting, slicing through cloak and pelt, smashing the trophies from their armour.
...
	Russ and the Lion had been created by the Emperor, schooled every stratagem known to the Imperium, made as strong and as fast and as guileful

Leman Russ: The Great Wolf pg. 151