Novak Djokovic and Alexander Zverev made surprise second-round exits at the Indian Wells Masters, while Roger Federer progressed on Sunday.
Making his ATP World Tour return after a spell out with injury, Djokovic slumped to a shock defeat against Japanese qualifier Taro Daniel.
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.
Federer had no such troubles at the ATP 1000 event, while Marin Cilic and Juan Martin del Potro also advanced.
DJOKOVIC, ZVEREV EXIT
In action for the first time since the Australian Open as he continued to recover from an elbow injury, Djokovic – the 10th seed – went down to Daniel 7-6 (7-3) 4-6 6-1.
Djokovic, a five-time champion at Indian Wells, now holds a 3-2 win-loss record this year.
The fourth-seeded Zverev was also stunned, suffering a 7-5 5-7 6-4 loss to Sousa.
Zverev held a 4-1 lead in the third set, but the German lost five straight games to be beaten.
Eyeing a sixth title at Indian Wells, world number one and defending champion Federer completed a 6-3 7-6 (8-6) victory over Federico Delbonis.
The Swiss star had won the first set when rain halted the second-round clash a day earlier and, while he did not have it all his own way when play resumed, he was still largely comfortable in advancing.
CILIC, DEL POTRO CRUISE
On a day when seven seeds – Lucas Pouille, Diego Schwartzman, Kyle Edmund, John Isner and Gilles Muller joining Djokovic and Zverev – fell, Cilic and Del Potro were untroubled.
Cilic, the second seed, disposed of Marton Fucsovics 7-5 6-3 and 2013 runner-up Del Potro outclassed Australian wildcard Alex de Minaur 6-2 6-1.