These are 2 completely different matches. I wouldn't decide the outcome based on the match with Fish - completely different players, different styles, outdoor/indoor, 2/3 and 3/5 sets, one is unofficial match the other is a R1 grand slam. Fish was not playing that well too. Besides Chardy won in straights sets the last time they played. Just some reasons to think about.
IMO this first match will be very hard, especially the first set, assuming Chardy will got that self confidence on his side. If Grigor plays well and wins it it will be a lot easier from then on.
Match with Fish only reveals that Grigor is in a great shape and very concentrated. A good sign to begin with...
I agree and in the RG match, Chardy got a lot of free points on his serve. Success for Grigor will depend on how well he reads Chardy's serve. If he's returning well and plays like he did in Perth, he stands a very good chance of winning the match.