He had elbow surgery in Switzerland shortly after that.
Federer won the Indian Wells championship for a fifth time last year, adding to his crowns in the Southern California desert in 2004, 2005, 2006 and 2012.
The clouds rolled in just before the start of their match on Saturday and after a short delay to start the first set they managed to play until the skies blackened and the heavy rains came in the second. In the victory, Chardy won 88 percent of his first serve points and 64 percent of his second serve points.
Chung, who made the final four at Melbourne Park in January, broke three times throughout the contest to prevail after one hour, 24 minutes.
Federer, who had looked slightly off his game in his rain-disrupted third round match against Federico Delbonis, was his dominant self on Monday, winning 89 per cent of his first service points while cracking six aces to just one double fault. His backhand, traditionally his most consistent and game-breaking weapon, bled errors-32 in all. Playing aggressively and making Djokovic move, Daniel would quickly erase the deficit and would end up taking the first set in a tiebreaker. He's not dropping sets let alone a match these days.
"I just completely lost rhythm, everything", Djokovic told reporters afterwards.
On a day when several seeds fell, the Serbian's loss and Zverev's departure at the hands of Joao Sousa were the biggest surprises.
"You're still battling inside of your mind", he added, referencing his recent elbow surgery.
For Daniel, a third-round meeting with world No. 47 Leonardo Mayer awaits. Federer has carried his form from last year and is currently unbeaten, while Nadal has struggled with injuries and is yet to complete a tournament in 2018.
Djokovic will now be hoping for a better showing at the next ATP Masters event he is scheduled to play in a few days time, the Miami Open.
"Sometimes it happens to be this way". "In Rotterdam I played five matches in a row", he said. Instead, it took 20 hours before a winner was decided.
Federer booked his place in the fourth round of the BNP Paribas Open with a straight-sets 6-2 6-1 win over Krajinovic.
"The Djokovic I know is like the Djokovic I have seen on TV, and he never misses a ball".