Novak Djokovic does not need to worry about accidentally hitting a US Open line judge with a tennis ball between points this year because there won't be any at Flushing Meadows.
Chair umpires will be the only on-court officials during matches at the New York grand slam.
The US Tennis Association and the sport's two leading professional tours, the ATP and WTA, announced on Monday that Hawk-Eye line-calling will be used for all competition courts at the US Open in 2021 and at seven of the nine US Open Series events preceding it.
A year ago, the USTA relied on the automatic system and dispensed with line judges at the US Open except for matches at the two main courts in Flushing Meadows, Arthur Ashe Stadium and Louis Armstrong Stadium.
During a fourth-round match at Ashe against Pablo Carreno Busta in September, Djokovic was defaulted from the US Open for inadvertently hitting a line judge in the throat with a ball after dropping a game.
It was a shocking and abrupt stop to the No.1-ranked Djokovic's 29-match winning streak.
After losing a game to trail 6-5 in the first set, Djokovic angrily swatted a ball behind him with his racket - and it went directly at the line judge.
Tournament referee Soeren Friemel ruled the match - and Djokovic's participation in the 2020 US Open - would end there, saying at the time: "We all agree that he didn't do it on purpose, but the facts are still that he hit the line umpire and the line umpire was clearly hurt."
The Australian Open, which Djokovic won in February for his 18th major championship, did not have any line judges on any courts.
Not surprisingly, Djokovic said he approved.
"I actually am in favour of technology. I think it's proven to be very accurate in this particular instance," he said at Melbourne Park when asked about ending the use of line judges.
"I don't see a reason why we need the line umpires, to be honest, if we have technology like this."
The US Open's main draw begins on August 30.