I actually went to edit that post and give a real breakdown of the Thiem backhand, but accidentally deleted it lol. The gist of it was Thiem’s standard rally ball is very good, heavy and hard to attack, but he doesn’t have the variety of a guy like Federer or even Wawrinka. He has a rather rigid wrist position, which I think is a big part of what helps him generate such pace and spin reliably. He just locks his arm into place and swings for the fences with his shoulder and upper body. But that restricts his ability to get those deft angles some other guys get (just go watch the 2015 FO final; insane angles from Wawrinka, and regularly), as well as lower balls and those defensive flicks that someone like Fed is famous for. (You see this also on his return; just doesn’t have that flexibility in how he orients the racquet face when he’s going topspin. Looks stiff and jammed up fairly regularly.)
His slice is decent, not the easiest to attack, but not a particularly biting shot. You can see a lot of times his follow-through follows a more vertical plane, not driving forward horizontally into the court. That means he’s not digging into the ball to give it that spin. His slice often kind of deadens the ball by sucking the energy out of it, but it’s not the type of skidding, unpredictable slice that other guys (like Fed obviously) can turn into a weapon at times. And I actually think he’s been overusing the slice lately. I mean, I haven’t seen much of him this clay season, but last fall and early this year he was slicing a lot when I thought he should be using his much better topspin backhand.
