Djokovic who had been out of action for nearly two months after his defeat against Korean Chung at the Australian Open had taken the second half of 2017 off to heal from an elbow injury.
On Sunday, the former world No. 1 could not even get past his opening match in Indian Wells, despite another extended break from the game he once dominated and after what he termed "a small medical intervention" on his troublesome right elbow.
"Just some inexplicable, uncharacteristic errors, but that's I guess all part of those particular circumstances that I'm in at the moment".
Federer returned to stadium court on Sunday afternoon and needed an hour to finish off his second round victory 6-3, 7-6 (8/6).
Speaking to the media after the match, Djokovic said, "It felt like my first match on tour".
The 34-old, who has seven career titles, pounded down 12 aces, including six in the deciding set.
The five-time Indian Wells champion raised his record to 13-0 on the season and 58-11 in the Indian Wells Tennis Garden he calls "paradise". He started quickly hammering a backhand victor to take the lone break of the first set and he would deny a pair of break chances when serving for the opener at 5-3.
"I just completely lost rhythm, everything, struggled a little bit with the health the last couple of weeks".
GETTYFederer took the first set 6-3
"To me, it's not that surprising", the defending champion said in California.
The 36-year-old Swiss marvel continues to defy the ageing process, claiming his 20th Grand Slam title and sixth Australian Open crown in January.
Yuki Bhambri of India pulled off a surprise when he toppled ninth-seeded Frenchman Lucas Pouille 6-4 6-4.
"The night-time is much deader".
Daniel who ranks 109 in the world also advanced to the third round. "The surface doesn't react so much; the ball doesn't travel so fast".
"Federer said", It's been a long time since I have been interrupted at night and have to come back the next day". Just didn't feel good at all, nerves were there.
On Monday, the third round wraps up with Federer back on court against Paris Indoor finalist Filip Krajinovic.