Peterborough United lacked belief in Tuesday's defeat at Huddersfield Town, said manager Robbie Savage.
Posh were beaten 4-1 at the Accu Stadium, with the Terriers inflicting their first defeat since Savage was appointed as boss earlier this month.
The result leaves Peterborough 21st in League One, with nine points from their opening 11 games.
"The lads are gutted in there because I just don't think they believed they could come here - like they did at Leicester - and win. I don't know why." Savage told BBC Radio Cambridgeshire.
"It's that quality in our final third, taking the wrong decisions. Backward steps, playing sideways, playing backwards a lot. That's not us, we've got to be braver and more positive. That's what we've done in the first three games.
"I said [to the players] at half-time, have a belief. They let us have the ball and were trying to hurt us in moments."
Posh are back on the road in their next league game, as they travel to 23rd-placed Bromley on Saturday before Tuesday's EFL Cup last-16 tie at Bradford City.
"Every game in this league is tough, but we've got to bounce back," said Savage.
"We've upped the sprint distances from 5,000m to 10,000m in two-and-a-half weeks so they are going to be tired. You could see at the end they were out on their feet.
"But they are going to have to build resilience. That's how we're going to train, that's how we're going to play because we are going to have to get up to those levels."