World number five Tomas Berdych crashed out of the Indian Wells ATP Masters on Sunday, falling in his opening match to 53rd-ranked Roberto Bautista Agut of Spain.
Bautista Agut, who toppled Juan Martin del Potro en route to the round of 16 at the Australian Open, used a punishing ground game to claim another top-10 scalp, 4-6, 6-2, 6-4.
"I played unbelievable," Bautista Agut said. "I was not serving very well, I had to play my best tennis from the baseline to win the match."
Berdych, an Australian Open semi-finalist who lifted the trophy in Rotterdam this year, arrived in California off a runner-up finish to Roger Federer in Dubai.
The 28-year-old Czech was at a loss to explain his off-key outing.
"Anything I touched today was basically bad and was wrong," he said. "Definitely my worst match that I had this year."
He credited Bautista Agut with making the most of his chances. The Spaniard opened the third set with a service break and fought off two break points in the sixth game to take a 4-2 lead.
Berdych did regain the break to knot the set at 4-4, but surrendered the decisive break in the next game.
Berdych said he'd felt a little off even in his warm up.
"I just started to feel not tight but not that crisp, like in the last couple of weeks."
World number two Novak Djokovic was the top men's seed in action on Sunday, opening his bid for a third Indian Wells title with a second-round meeting with Romanian Victor Hanescu.
Djokovic, who won the title in 2008 and 2011, has played sparingly this season, falling in the quarter-finals of the Australian Open to eventual champion Stanislas Wawrinka and losing in the semi-finals at Dubai to Federer.
Men's sixth seed Juan Martin del Potro had been slated to open his campaign, but the Argentinian withdrew with a left wrist injury.
Polish second seed Agnieszka Radwanska was the top woman in action, taking on Germany's Annika Beck in a third-round match.
Former champions Caroline Wozniacki and Jelena Jankovic were also playing third-round matches.