Between them, Alcaraz and Sinner have won the last eight Grand Slam titles, with an even split of four each.
Djokovic has been unable to find a way past the world No. 1 and No. 2 this season. He was beaten by Sinner in the semi-finals at the French Open and Wimbledon, while Alcaraz knocked him out of the US Open in the last four in September.
The Serbian has 24 major titles to his name and is aiming for a 25th to go clear of Margaret Court at the top of the all-time list for Grand Slam victories.
Speaking about how he hopes to stop the dominance of Alcaraz and Sinner, Djokovic said: “I’m still working my hardest that I possibly can in the circumstances to challenge the guys or to challenge myself primarily and really see how I can do on all the tournaments that I take part in.
“Of course, best-of-three, duration of the tournament, ideally seven days, that’s where I feel I have a better chance to win a trophy or to make a significant result.
“Other than those matches that I lost to these best two players in the world, I think I played really good tennis in Grand Slams and reached semi-finals in each one of them. So it speaks about the level and the consistency and so I’m pleased with that.
“But at the same time there’s a part of me that always is a winner, that, you know, wants to be the best. I’ve been fortunate to experience the greatest thing.”
Djokovic leads the head-to-head record 5-4 against Alcaraz and has won four of their last six meetings.
But Sinner has won the past five matches against Djokovic to improve to 6-4 against the former world No. 1.
“It is not ideal when you really are playing big matches and you’re losing against currently the best players in the world,” said Djokovic.
“But nevertheless, that’s not discouraging me to keep going. I don’t play tennis only for the sake of making results and winning trophies, there’s several other reasons why I keep going.”
Djokovic’s son Stefan, daughter Tara and wife Jelena are regularly in attendance at his matches, and he is taking the opportunity to inspire his children.
“My son, he plays tennis more and so he follows what’s going on,” he said. “He was really insisting on travelling with me to China. He wants to travel with me everywhere, but he has to do school, and it’s not that simple.
“But he’s really in love with tennis and the sport.
“My kids and my wife are my biggest supporters and when they are in the stadium you’ve seen them how they support, how passionately they care about and play with me every single point.
“So, of course, me seeing them on the stands it’s even more inspirational. I love to have them.”
Djokovic plays Cilic on Friday in Shanghai.
