Jan-Lennard Struff produced one of the best displays of his career to beat Alexander Zverev 6-3 6-1 at the BNP Paribas Open in Indian Wells.
The 28-year-old German reached the fourth round in style by dominating his match against Zverev, who won last year's ATP Finals.
"It's amazing," Struff said afterwards. "I played a good match. He was missing some shots but at the end of the day I'm very happy with that [performance]."
"It's about getting healthy and about recovering and preparing myself for Miami," said Zverev, who revealed that he was suffering from a virus. "Miami is the tournament I do well in [compared to Indian Wells], history-wise."
Struff, who is 11/5 to beat Milos Raonic in the next round, has never got past the third round of any Grand Slam tournament before, although he did briefly hit the headlines in 2016 when he defeated the then world number three Stanislas Wawrinka at the Paris Masters.
Raonic was forced to hit back from a break down in the third set to beat the qualifier Marcos Giron. The Canadian is 4/11 to beat Struff, who is 6/1 to come out on top in three sets.
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