They’re moonballs. I’ve seen the camera angle and I can tell when they’re floating.You need to watch court level views of Nadal's shots. The camera angle doesn't do them justice. They look like moonballs from above, but in reality they are 3500rpm rockets traveling at an average speed of about 78 mph.
Nadal has one of the highest average shot speed on tour. Right there with Del Potro.
Almost every shot from Thiem is faster too