The Spanish world number three crashed out 6-2, 6-0, 7-6 (7/5) against the Czech seventh seed he had beaten the last 17 times they met.
Asked about his "so-so" match, Nadal quickly corrected the reporter: "No, not a so-so game today, it was very bad. You can say that, no problem.
"I didn't play with the right intensity, with the right rhythm," he added.
"I didn't compete the way I wanted to compete in the first two sets and that's something that I don't like."
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