Zinedine Zidane said Real Madrid's first defeat since his return can be partly explained by a lack of motivation.
Madrid lost 2-1 at in-form Valencia on Wednesday, Goncalo Guedes and Ezequiel Garay scoring before Karim Benzema's consolation header.
Los Blancos had won their two previous matches under Zidane, although they needed Benzema's late strike to down bottom side Huesca at the weekend.
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Madrid are 13 points behind league leaders Barcelona but 11 clear of fifth-placed Valencia, leaving them with little to play for.
"They will try to finish the season in the best possible way," Zidane told a news conference.