Tommy Haas has described his fourth-round victory over Novak Djokovic at the Miami Masters as "crazy".
The 34-year-old German, who has been plagued by injury throughout his career, defeated the world number one 6-2 6-4 on Tuesday to reach the quarter-finals of the tournament.
"You know, even looking at Novak Djokovic's results the last two years, two-and-a-half years, it's just crazy," Haas is quoted as saying by Tennis.com. "It's something really special."
Haas will face French 11th seed Gilles Simon for a place in the semi-finals.