Fulham manager Marco Silva said Crawley Town showed more desire than his team in Tuesday's League Cup second-round clash, where the Premier League team were knocked out after a 2-0 defeat away to the fourth-tier side.
Silva made 10 changes for the trip to Broadfield Stadium as Fulham, who are seventh in the top-flight after three matches, were beaten by Crawley, who are 84 places lower on the English ladder.
"It was a bad performance, definitely, and of course the result as well," Silva said. "It puts us out of a competition that we wanted to win.
"Congratulations to them, from the first minute they wanted it more than us, and after that we lost a little bit of control in the game, started to make some mistakes, and they scored, which made it more difficult for us."
Crawley manager Kevin Betsy described their win as "unbelievable".
"Little Crawley Town beating Premier League Fulham... What we have done is phenomenal," Betsy told the BBC. "We had a plan of how we wanted to play and that will be our blueprint going forward."
Everton avoided any slip-up as they beat third-tier Fleetwood Town 1-0 in the League Cup second round to claim their first win of the season on Tuesday.
Frank Lampard's struggling side were one of 10 Premier League clubs in action across 21 ties and edged through to round three thanks to Demarai Gray's 28th-minute goal.
Lampard said: “I was really pleased with the attitude but the intensity and quality at times wasn’t as good as it should have been and we should have controlled the game better.
“It was a good indicator of where we are at the moment because we know we have to improve but it was good to get through.”
Leicester City, who like Everton have started the season poorly, gained some relief as they scraped through on penalties against Stockport County after a 0-0 draw.
Premier League Bournemouth also required penalties to knock out Norwich City who were relegated from the top-flight last season. Norwich were poised for the third round as they led 2-1 at Carrow Road but Brooklyn Genesini equalised in stoppage time before the visitors won the shootout.
Steven Gerrard's Aston Villa fell behind at third-tier Bolton Wanderers but hit back to win 4-1.
Premier League newcomers Nottingham Forest eased to a 3-0 win at Grimsby Town and Wolverhampton Wanderers beat second-tier Preston North End 2-1.
Crystal Palace scored two late goals to win 2-0 at Oxford United, their first win in the competition since 2018.
Brentford bounced back from their weekend defeat by Fulham to win 2-0 at fourth-tier Colchester United.
Che Adams maintained his scoring form with two goals as Southampton won 3-0 at Cambridge United.
Adams also scored twice at the weekend as Southampton beat Leicester City.
Premier League clubs playing in European competitions are exempt until the third round of the League Cup.