Of course, it was a monumental loss. It was the worse loss of the year for any player.
It is a rare event. He is only the 7th man to have been defaulted in the Open Era.
A default is worse than a retirement, or even a triple bagel.
Even unintentionally, he was kicked out for careless or reckless aggravated behavior against a defenseless, innocent woman, who was doing her job, looking at the line, not at him. It took only 1/2 second for the ball he hit at about 86 kph to reach her throat. He was lucky it didn't more seriously injure her. It would be embarrassing for any player, much less the #1.
He was stripped of points and prize money for the tournament, and could have even been suspended.
He is the highest ranked player to suffer a default (McEnroe was #4 in 1990), so some might say it is the greatest loss all time (GLOAT), but I'm not sure about the Pro-Am Era..
Shamefully,
masterclass