If the Boks were playing our current game Marius would have scored many more. He did exactly to Umaga what you were raving about Willie...he showed him inside and beat him on the outside. And his 60 m try where he gassed the Aus sie backline in 2002 showcased his pace.
The difference is when Tuquiri got the ball in space Marius hunted him down and scythed his legs away with a perfect low tackle. JJ would have dusted his shoulders. He can't be a reliable centre until he learns how to make a low tackle.
