Indian Wells - Ailing world No 3 Alexander Zverev was sent spinning out of the ATP Indian Wells Masters on Monday, falling in straight sets to 55th-ranked Jan-Lennard Struff.
Struff had lost all four prior encounters against his fellow German, but he made quick work of the 21-year-old star, breaking him once in the first set and three times in the second to win in 70 minutes.
"I've been sick for a week," said Zverev, who lost the Acapulco final to Australian Nick Kyrgios the week before Indian Wells began.
"That hasn't changed, unfortunately.
"I think I just got unlucky, I got a virus somewhere and that's how it is."
Zverev, the owner of three Masters 1000 titles who has never made it to the quarter-finals at Indian Wells, said he would now focus on recuperating and preparing for the Miami Masters, where he'll be hoping to improve on his runner-up finish to John Isner last year.
"Now it's about getting healthy and about recovering and preparing myself for Miami, because Miami is the tournament I do well in, history-wise," he said.
"Here I have always struggled."
Struff next faces 13th-seeded Canadian Milos Raonic, who rallied from 4-1 down in the third set to beat US qualifier Marcos Giron 4-6, 6-4, 6-4.
Giron, 25, looked set to claim the biggest win of a career that has been hindered by two hip operations when he took a 4-1 lead in the third set.
But Raonic, runner-up at Indian Wells in 2016, called on all of his experience to turn things around against the American, who had never won two ATP Tour matches in a row until this week.
"He came up with the goods and definitely pushed me sort of to the brink there where I was getting a little bit frustrated," Raonic said.
"I just kept trying to plug away. There were two games that I had break chances to get back into the third, and I didn't make it count. Luckily I made the last two count.
"I'm proud of the way I competed today. That's what got me through," said Raonic, who fell to Struff in the first round at Dubai last month.
Results on Monday in the BNP Paribas Open WTA and ATP Masters hardcourt tournament (x-denotes seeded player):
Gael Monfils (FRA x18) bt Albert Ramos (ESP) 6-0, 6-3
Ivo Karlovic (CRO) bt Prajnesh Gunneswaran (IND) 6-3, 7-6 (7/3)
Dominic Thiem (AUT x7) bt Gilles Simon (FRA x27) 6-3, 6-1
Jan-Lennard Struff (GER) bt Alexander Zverev (GER x3) 6-3, 6-1
Milos Raonic (CAN x13) bt Marcos Giron (USA) 4-6, 6-4, 6-4
Yoshihito Nishioka (JPN) bt Felix Auger-Aliassime (CAN) 6-7 (2/7), 6-4, 7-6 (7/5)
Miomir Kecmanovic (SRB) bt Laslo Djere (SRB x30) 6-2, 7-6 (7/3)
Naomi Osaka (JPN x1) bt Danielle Collins (USA x25) 6-4, 6-2
Belinda Bencic (SUI x23) bt Ekaterina Alexandrova (RUS) 6-4, 6-2
Anett Kontaveit (EST) bt Anastasia Sevastova (LAT) 5-0 retired
Karolina Pliskova (CZE x5) bt Ysaline Bonaventure (BEL) 6-3, 6-2
Venus Williams (USA) bt Christina McHale (USA) 6-2, 7-5
Mona Barthel (GER) bt Julia Goerges (GER x15) 7-5, 1-6, 6-4
Aryna Sabalenka (BLR x9) bt Lesia Tsurenko (UKR x24) 6-2, 7-5
Angelique Kerber (GER x8) bt Natalia Vikhlyantseva (RUS) 3-6, 6-1, 6-3