Tottenham Hotspur have been stunned by Pacos De Ferreira in the Europa Conference League.
Spurs are down 1-0 after the first leg of their qualifying tie, which was played in Portugal.
Nuno's side were riding high after beating title favourites Manchester City last weekend.
But the manager admits the "feel good factor" has disappeared after the shock midweek loss.
The Portuguese named a completely different starting XI from the one which beat City on Sunday.
It turned out to be the wrong decision as Spurs delivered an insipid display, with Lucas Silva scoring the decisive goal.
The Premier League outfit must win next Thursday's second leg at Tottenham Hotspur Stadium.
"Nobody likes to lose a game," said Nuno. "Nobody likes to not play good.
"The feelgood factor disappeared. This is football, ups and downs. The players have to bounce back."
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