Heather Watson has admitted that she failed to produce her best tennis during her defeat to Irina-Camelia Begu in the first round of Indian Wells.
The British number one downplayed concerns over her fitness following the 6-2 6-4 defeat, conceding that she "wasn't really there" on the day.
"Today wasn't my best day at the office," she told BBC Sport.
"I didn't really play well but my opponent is a great player and I feel like these courts really suit her game, and she played very smart. I wasn't really able to keep many balls in play. I wasn't really there today.
"I feel the courts are just very different, like a clay court - they're very, very slow and it bounces very high here."
British number two Laura Robson also bowed out of the tournament at the first hurdle, losing 2-6 7-6(2) 6-1 to Sweden's Sofia Arvidsson.