The Scot was in formidable form against Simon to continue his run of not dropping a single set so far at Melbourne Park to four matches.
Murray admitted that a fresh Chardy should pose a live threat when the pair meet in the quarter-finals on Wednesday.
He said: "I just had to focus on my side of the court. He's one of the best movers on the tour and he was definitely restricted today.
"But that's exactly what Grand Slam tennis is, it's a tough, physical battle and you just have to get on with it.
"I've always had great support down here. I play Chardy and I lost against him last time in Cincinatti so I expect a tough match."
The third seed remains on course to meet Roger Federer in the semi-finals as he chases a second Grand Slam title.