"I just wanted to go out and see".
World number one Roger Federer barely raised a sweat en route to the last 16 at Indian Wells, while Dominic Thiem succumbed to injury.
Djokovic was beaten 6-7, 6-4, 1-6 by world No109, Taro Daniel, who had made the main draw as a qualifier.
After that defeat, he chose to undergo a medical procedure on his elbow in Switzerland: one the 30-year-old Djokovic has yet to explain in detail.
Federer is out on his own in terms of Grand Slams won on the ATP Tour with 20 and is widely regarded as the best male tennis star to have played the sport. "I mean, I just completely lost rhythm, everything", he said.
It was the former world No.1's first match since returning from an injury, which forced him to undergo a surgery earlier in February.
Australian Open semi-finalist Hyeon Chung, meanwhile, trumped Tomas Berdych.
There was no let up from Federer in the second set.
Krajinovic had no answer for Federer's serve or relentless return game and ended up winning just 31 of the match's 93 points. "Very weird", Djokovic said. "And even though you don't have pain, you are still thinking about it because it's something I've been feeling and dragging for over two years".
"It's been a long time since I have been interrupted at night and have to come back the next day".
Chardy, who came into the all-French tussle with an unbeaten record against Mannarino from their three previous meetings, edged the opening set before the French No 2 hit back to force a decider and claim his first set against the 31-year-old. "Filip's wasn't so good and then things go quickly", Federer told Sky Sports in a post-match interview.
Daniel, who is ranked 109th in the world, advanced to the third round where he will face Gael Monfils of France.
Having lost seven games in a row, Krajinovic finally got on the board again with a hold for 3-1 in the second.
Argentina's del Potro, who is fresh off winning the Mexican Open title in Acapulco, hammered five aces and broke de Minaur's serve five times.
Borna Coric of Croatia upset 13th seed Roberto Bautista Agut 6-1, 6-3 and Spain's Pablo Carreno Busta defeated Daniil Medvedev 6-1, 7-5.