Djokovic vows shock Australian Open loss is 'not beginning of the end'
The world number one notched up 54 unforced errors and failed to create a single break point, losing 6-1, 6-2, 6-7 (6/8), 6-3 as his 33-match winning run came to an end at Melbourne Park.
Ten-time champion Djokovic said he was "shocked" by the level of his performance against fourth-seed Sinner on Rod Laver Arena, where he had never previously lost a semi-final.
"He's deservedly in the finals," said the 36-year-old. "He outplayed me completely today.
"Look, I was, in a way, shocked with my level, you know, in a bad way. There was not much I was doing right in the first two sets.
"I guess this is one of the worst Grand Slam matches I've ever played. At least that I remember."
Defeat ended Djokovic's bid for a record-extending 11th Australian Open crown and a 25th Grand Slam - which would have taken him one clear of Margaret Court on the all-time list.
The Serbian is already out on his own in the men's game, with his tally of 24 putting him two clear of the injured Rafael Nadal and four ahead of the retired Roger Federer.
He said his form at this year's Australian Open, where he had not lost since 2018, had been sub-par.
"This tournament hasn't been up to my standard or criteria or the level that I would normally play or expect myself to play, but that doesn't necessarily mean that it's the beginning of the end," he said.
Djokovic is 14 years older than Sinner, who is part of a young generation of players hungry for success, but he has no intention of hanging up his racquet yet.
"I still have high hopes, you know, for other Slams, Olympics, and whatever tournaments that I'll play," he said. "It's just the beginning of the season.
"This has been a very special city, best, by far, Grand Slam of my career," he added.
"I just hope that I'll get a chance to come back to play at least another time and go through the emotions once more."