Novak Djokovic's former coach has admitted his US Open disqualification on Sunday has left the 17-time Grand Slam champion 'in pain'.
The world No 1 was booted out of the Grand Slam in dramatic fashion when he swiped a ball to the back of the court angrily, only for it inadvertently to strike Kentucky-based official Laura Clark in the throat.
Clark fell to the floor and after consultation with the referee, officials determined they had no option but to disqualify Djokovic. It was his first loss of 2020 and while he shook hands with opponent Pablo Carreno Busta before departing, the episode has knocked his reputation in sport.
Novak Djokovic 'is in pain' after his US Open disqualification saw him vilified across sport
Djokovic was frustrated and fired a ball behind which struck the line judge in the throat
Kentucky-based line judge Laura Clark was knocked down and Djokovic was disqualified
Radek Stepanek (right) knows Djokovic better than most having spent time coaching him
Radek Stepanek coached Djokovic alongside Andre Agassi for several months between 2017 and 2018 and he told CNN that he suspected the Serb was suffering.
'I know he is very sad inside himself and he is in pain,' Stepanek, former world No 8 told CNN.
'He is in pain because it was unintentional and, in that moment, the pain is bigger.
'And it's hard for him because we know how hungry he is to become the player with the most grand slams. I believe he felt -- everyone felt -- this one should be for him, reachable.
'All these circumstances make it very sad for him and in the first moment, empty, because I believe he himself knew that it was wrong that she got hit.'
Djokovic was handed a fine of $10,000 (£7,600) for 'unsportsmanlike conduct' and was also stripped of his $250,000 (£190,000) prize money for reaching the last-16.
He left the Flushing Meadows site on Sunday without facing the media and waited hours before he released a statement on social media to apologise for his actions.
Djokovic wrote: 'This whole situation has left me really sad and empty. I checked on the lines person and the tournament told me that thank God she is feeling ok.
'I'm extremely sorry to have caused her such stress. So unintended. So wrong. I'm not disclosing her name to respect her privacy. As for the disqualification, I need to go back within and work on my disappointment and turn this all into a lesson for my growth and evolution as a player and human being.
'I apologise to the US Open tournament and everyone associated for my behaviour. I'm very grateful to my team and family for being my rock support, and my fans for always being there with me. Thank you and I'm so sorry.'
Her name, while not revealed by Djokovic, did eventually come to