Interesting bits in that video, I like his backhand a lot and now understand why he is different than most pros and especially American ones. Not too happy with his forehand but we will see. His return numbers are quite low, but not too bad considering his growth patter, while his serve is holding up well. He looks very young and his athleticism will improve.
Zverev has been serving great and has let Klein dominating the rallies. Hard to see this Alex doing that, but it will be nice to see how his backhand will work. I guess much down-line stuff incoming.