When Novak Djokovic defeated Roman Safiullin in the Shanghai Masters Round of 16 on Wednesday, he was displeased with the chair umpire. Djokovic got into a heated argument with Ignacio Forcadell, voicing his disappointment.

The ATP has implemented a new regulation that immediately initiates the shot clock, disregarding any potential events that may occur in between exchanges. To defend himself, the chair umpire said the regulation had been in place for a while.

After winning 6-3, 6-2, Djokovic will play Jakub Mensik in the quarterfinals. When Djokovic defeated Alex Michelsen in the second round, he also lost a heated argument with a chair umpire. The incident occurred during the second set of the match when he ran out of shot time and was given a time violation.

After defeating Safiullin, Djokovic gave himself a performance rating of "pretty close to ten." These matches and the one I played yesterday night maybe some of the finest I've played in a long time. I'm simply having fun on the court. Hitting a tennis ball on the court may be a lot of fun when you're playing well and feeling good."