It was La Roja's first qualification defeat in 37 matches, but Del Bosque was pleased with his side's overall performance.
"We're not in good spirits after a defeat. We're ready to play Sunday's game. Personally I'm fine, even if I'm not very expressive. I know we can't always win and this is a long journey," he told AS.
"There was no difference with other games we've played, for example against Macedonia. We played a team that was very deep and we had full control of the game.
"They had three or four chances and scored twice. We had a lot of chances but they didn't result in a goal. It's difficult to explain. We're not getting any luck. We had a lot of control and couldn't have more. We lacked the touch in front of goal that we've had at other times."
Spain travel to Luxembourg tomorrow evening.