Jordan Pickford insists England were not complacent as they slipped to defeat against the Czech Republic on Friday night and are itching to bounce back in Bulgaria.
The Three Lions could have booked their place at Euro 2020 with victory in Prague but instead surrendered an early lead to lose 2-1 - their first qualifying defeat of any kind in over a decade.
Harry Kane's fifth-minute penalty had the visitors ahead, only for Jakub Brabec to level soon after and debutant Zdenek Ondrasek to come off the bench and win it for the Czechs.
England had not tasted a defeat in either European Championship or World Cup qualifiers since losing to Ukraine in 2009 but, having won their opening four Group A games this time around, Pickford denied the players were resting on their laurels.
"We knew it was going to be tough," he told BBC Radio 5Live.
"As a group we trained well all week, we know the ability and depth we have in the squad so we were disappointed as a group but the best thing about football is we have got a game on Monday to bounce back.
"We knew it was going to be a tough game, we weren't complacent about that, we trained hard all week to come into this game to win and to qualify but fair play to the Czech Republic, they made the game hard."
The result means even victory against Bulgaria may not be enough to seal qualification ahead of next month's final two games at home to Montenegro and away in Kosovo.
But, following a rare defeat at this level, Everton goalkeeper Pickford believes lessons can be learned from the night.
"I feel like we were on it as a side, it was just a tough game and we didn't get a crucial second goal," he added.
"It just wasn't to be and wasn't our night but if we can learn from a defeat then we can get better as a squad."