Tottenham boss Nuno Espirito Santo said the club's "feelgood factor disappeared" as they were beaten by Pacos de Ferreira in the Europa Conference League play-off first leg.
He left the entire starting XI from Sunday's 1-0 win over Manchester City - and Harry Kane - at home.
They were very poor in Portugal.
Lucas Silva ran in behind Cristian Romero too easily to latch on to Nuno Santos' through ball and slot into the bottom corner for the only goal.
"Nobody likes to lose a game," said Nuno. "Nobody likes to not play good. The feelgood factor disappeared.