"We started the game well. We were doing a good job defensively, although it's true we didn't get near our opponents' box," Gracia told reporters at a press conference.
"Then we had the clearest chance of the game so we were going well. But in the second-half the long ball caused us problems and the ease they had in getting to our goal made things more difficult.
"We tried to make it 3-2 in the final minutes but we couldn't."
The defeat left Osasuna in 16th position in La Liga, just two points outside of the bottom three.