Replying to both posts above:
I watched the entire match. I do not know the behavior of this umpire with other players, but,
in this match, he was doing the normal job regarding the shot clock. Maybe what bothered NK is that he calls the score on average quicker than the other umps -- so the shot clock starts earlier, but the thing is that whatever he was doing was consistent -- he would call it quicker after quick points, he would let the crowd finish to applaud when it was too loud, he was doing the same thing for both players. He even started to give a bit more time for NK after he complained the first time, but he simply wouldn't shut up.
Actually, he got away from taking a one game penalty he actually deserved -- it would be the third violation in a row when he broke two racquets in a toilet break. So he was in fact helped by lenience and not the other way around.
Also, and this is important, at the time NK complained at the first time, he never got even close to getting a time violation. Honestly the guy was just looking for a reason.
This will probably go down as a match he lost because of his head, when what actually happened was probably the opposite. The first set was basically one way traffic for Kachanov, in the middle of it NK started the show, and then Kachanov was not cool enough to close it out when he served for it (double faulted, made a lot of UFE's and basically gave the game away). Up untill he served at 5-4 he just lost three points on serve (one DF), while on the other hand being in most of NK's serve games. After the show started there was a sequence of 15 points where NK score 13 of those points.
KK still had a set point when NK served at 5-6, which was saved with an 142 mph ace on
second serve.
(Kudos for NK for having such balls). Then end result of this crazy set is a crap of tie-break from Kachanov and Kyriogs winning it.
So, he was smart enough and turned around the match. But he took it to the next level -- I agree with
@Moxie that it became pure gamesmanship at some point. Then, kudos to Kachanov that from that point got his act together, focused on his game, kept his mouth shut and deservingly won the match.