As you say a little scary but he was mostly in control of the match and himself. It was good to see how much he wanted (and expected) to win. Taylor Fritz next could be quite a match.
Fritz has still to play tonight, but if it goes true to form he'll win.
According to the OOP for Thursday the match will be last on court around 9:00 pm local time, 2:00 am BST,
which pretty much rules those of us in Europe out.