Updated

By Mark Lamport-Stokes

INDIAN WELLS, California (Reuters) - Rafa Nadal described his stunning semi-final loss to Ivan Ljubicic on Saturday as an "accident," and felt he had been playing close to his best at the Indian Wells ATP tournament.

The Spanish world number three was upset 3-6 6-4 7-6 by the big-serving Croat at the Indian Wells Tennis Garden after he had squandered three break points in the sixth game of the second set to lead 4-2.

"It was an important accident, and I have to learn to try to play more aggressive next time, try to convert the opportunities.

"But for the rest, nothing to say, no? I was feeling I was playing better than probably ever on this court."

Saturday's loss to Ljubicic, only his second defeat by the Croat in seven career meetings, left him with a win-loss record this season of 12-3.

"Since I start 2010, I was playing at my best," the 23-year-old Spaniard said. "I was playing at my best all the time.

PLAYING UNBELIEVABLE

"On hardcourts, I won when I came with big confidence, when I was playing unbelievable. This year, I play at all the tournaments really well.

"Only in Australia, the first two matches I didn't play like my best, but against Murray I was playing fine," added Nadal, who was forced to withdraw from his Australian Open quarter-final against Briton Andy Murray in Melbourne.

"This tournament I was playing very good, having very good victories, beating a very difficult opponent like (John) Isner, and later against a very good (Tomas) Berdych.

"So I happy about how I did here. I am playing at my best level. I know that. But just not today."

"After losing an important singles, the victory in doubles makes me happy. Always is nice to win the tournament, no?"

(Editing by Greg Stutchbury)