5 games in a row for Andy. 6 - 3 3 - 0 * ( saved break point there )
Looks as if maybe really going for his first serve here. 1st serve % only 43% but 5 aces and 19 / 21 points when he gets it in. Had another ace on second serve followed by his second DF in the latter part of that game.
I only watched the end of the second set but to try and answer your question Indiana Russell was able to maintain his consistency in the longer rallies and as a result win alot of those points. He didn't make too many unforced errors. I wouldn't say Andy was shooting at second serves its just that Russell's first serve isn't great so Andy was making all his returns into the court. Just a quirk of fate that these stats are like they are. Another note I would make is that Andy looked pretty tired at the end of some of the rallies and I have read that he has done very little fitness training in the five weeks since the Aussie open so that could be a potential problem for later on in the tournament.
Also, I wonder just how hot it was? I noticed that the ball girls holding the umbrellas frequently had one of the others come and give them a drink. Also I suspect it was a bit gusty - they sometimes seemed to have a bit of a struggle to hold onto the brollys, and their dresses were blowing about sometimes.
Same for both players of course, but some deal with hot and windy conditions better than others.
Again, it wasn't the best performance by Murray but it didn't need to be and he got through in straight sets so minimised the time he had to spend on the court.