But the 31-year-old wasn't happy with Carlos Ramos, accusing the the Spanish official of "double standards" during an ongoing battle in the two-hour, 35-minute encounter. I didn't harm the grass. "He even threw the racket in the fourth set and the umpire said he didn't see him so I get the warning, he doesn't", added the Serb.
"I think it's not fair, but it is the way it is in the midst of the emotions of a match".
Despite his anger, Djokovic still reeled off 10 of the last 12 games of the quarter-final. "I've been building the last couple of weeks on the level of tennis that I've played the last couple of months, the last couple of clay-court tournaments and Queen's".
"I feel like I'm peaking at the right moment", declared the 12th seeded Serb after joining Americans John McEnroe and Pete Sampras in fourth place on the list of most Wimbledon semi-final appearances in the Open Era.
"You think I ruined the court for just throwing my racket (down)?"
Djokovic looked in control in the first set.
The 2011, 2014 and 2015 champion was clearly unsettled by the dispute, quickly surrendering the set.
However, he prevented further damage when he held from 0-40 at 2-2 in the third set, and the hold would prove significant as he responded well to break Nishikori twice in succession.
Nishikori, who had won only two matches in 15 meetings with the 12-time major victor, broke for 1-0 in the fourth but was broken straight back.
"Double standards, my friend", screamed the former world number one.
That didn't seem to affect his focus, though, and neither did a time violation he was given when serving at 4-2, 30-30 in the fourth set.
In the middle of a quarterfinal clash against Japanese opponent Kei Nishikori, Djokovic grew increasingly frustrated that the second set was not going his way.