I think what people tend to forget is that Murray in the last 5 years has always played well in the Australian Open (notably the first week) and often very rarely lost sets till the QF/SF...
2009: Won all matches in straight sets till losing
2010: Won all matches in straight sets till SF (lost 1 set)
Draw included: Anderson, Isner, Nadal
2011: Won all matches in straight sets till SF
2012: Lost a set in R1, but won all matches till SF
Draw included: Harrison, Nishikori
The pattern is pretty clear, he gets through the first week (just like this year) with the minimum of amount of energy. It's only till the SF does he start to lose a couple sets.
If Murray was getting to the Roland Garros final with straight set wins then it would be more notable but it shows these matches in Melbourne for Murray shows that he's quite comfortable on this surface in the heat.