Five-time winner Novak Djokovic is out of the BNP Paribas Open after suffering a three-set defeat to Japanese qualifier Taro Daniel in the second round.
Djokovic came from a set down to level the match against the World 109 but then fell apart in the final set, as Daniel triumphed 7-6 (7-3) 4-6 6-1.
Djokovic is a 12-time Grand Slam champion and former World No 1 but was only seeded 10th here, having taken six months off after Wimbledon last year and then undergone surgery following a fourth-round loss at the Australian Open.
After his defeat, a bemused Djokovic said: “It felt like the first match I have ever played on the tour, very weird.
“I just completely lost rhythm, everything, struggled a little bit with the health the last couple of weeks.
“I was grateful to be out on the court after surgery that quickly but, at the same time, just didn’t feel good at all. Nerves were there. I made so many unforced errors.”
Djokovic had four aces but served poorly overall, finishing with four double faults, and the Serbian made 62 unforced errors in total.
Daniel, who beat Britain’s Cameron Norrie in the first round, will next meet Leonardo Mayer, who defeated Ruben Bemelmans 6-4 6-1.
Holder Roger Federer avoided the same fate as Djokovic, though the Swiss top seed was pushed hard by Argentine Federico Delbonis in a match that was completed on Sunday after being halted by rain on Saturday.
Federer staved off a set point in the second set tie-break to beat Delbonis 6-3 7-6 (8-6) and he will face 25th-seed Filip Krajinovic in the third round on Monday.
“It’s been a long time since I have been interrupted at night and have to come back the next day,” said Federer.
“In the night-time, the ball is much more deader. The surface doesn’t react so much.”
Sixth seed Juan Martin Del Potro took just under 70 minutes to beat Australian Alex de Minaur 6-2 6-1 and Australian Open runner-up Marin Cilicis also through after a 7-5 6-3 straight sets win over Marton Fucsovics.
But World No 5 Alexander Zverev is out, having lost a two hour, 23 minute marathon to the 85th-ranked Joao Sousa of Portugal.
Sousa eventually prevailed 7-5 5-7 6-4 to set up a third round match against Milos Raonic, who beat 17-year-old countryman Felix Auger-Aliassime 6-4 6-4.
Frenchman Gael Monfils survived a match point before beating big-serving American John Isner 6-7 (5-7) 7-6 (7-3) 7-5 in a contest that had only one break.