Not a surprising result. Night+humidity+already slow court=horrible conditions for Harrison. And knowing Rainer he probably counterpunched Ryan's shots a lot and kept him off balance, and Ryan made tons of errors. Also Rainer is a better returner than all 3 of Raonic/GGL/Chardy, so he's going to get more serves back and force Ryan to play, and he's still a bit erratic at this point in his development. Lastly, the weight of expectations on Ryan from IW potentially could have been weighing on his psyche. But we all have to remember he's only still a kid, and will only keep improving from here.
Great to see Rainer getting some good results when some on this forum wrote him off