Former world number one Novak Djokovic suffered a surprise defeat by Benoit Paire in the Miami Open second round.
The Serb, now ranked 12th as he continues his return from an elbow injury, lost 6-3 6-4 to the French world number 47 in just 69 minutes.
It is Djokovic's third consecutive defeat since he reached the Australian Open fourth round in January.
Paire will next play Serbia's Filip Krajinovic, who ended British number five Liam Broady's run on Friday.
Krajinovic, seeded 22nd, beat world number 169 Broady 6-3 6-2 in 71 minutes.
Juan Martin del Potro, who won at Indian Wells last time out, moved into round three with a 6-4 5-7 6-2 victory over Dutchman Robin Haase.
The world number six will play Kei Nishikori after the Japanese registered his first ATP Masters 1000 win in 10 months with a 7-6 (7-4) 4-6 6-3 win over Australia's John Millman.
Nishikori returned to the ATP Tour in February after a lengthy lay-off with a wrist injury, but withdrew from Indian Wells earlier this month with illness.
He saved five set points in the opening set and struggled with his forehand, but held on to outlast Millman in two hours and 52 minutes.
Seventh seed David Goffin was beaten in straight sets by Portugal's Joao Sousa.
The Belgian, who was making his return after injuring his eye at the Rotterdam Open in January, lost 6-0 6-1.
Sousa hit 18 winners to Goffin's nine, with the Belgian making 26 unforced errors in the 62-minute match.