Fulham manager Slavisa Jokanovic believed his side were undone in the 2-1 loss to Bristol City by failing to concentrate for the entire game, after creating a number of chances.
Tammy Abraham grabbed the winner after Aaron Wilbraham cancelled out Lucas Piazon's opener and Fulham's Cauley Woodrow missed a second-half penalty.
Fulham got the breakthrough their play deserved on 15 minutes when Piazon met Woodrow's cross with a diving header.
After being under the cosh for the majority of the first half, City equalised when Wilbraham was able to chip his effort over onrushing keeper Jesse Joronen.
Woodrow was brought down in the area in the second half by Taylor Moore, but debutant Ivan Lucic was able to save the resultant spot-kick.
The miss appeared to galvanise City, who got more of a foothold in the contest. Wilbraham was guilty of two glaring misses before Abraham turned in a cross by Callum O'Dowda to grab a victory that seemed unlikely in the first half.
"You have to play from the first minute to the last in all the games. It's disappointing for us but we made many chances in the first half, we missed the penalty in the second half," he said.
"To be honest, at the end of the game Bristol City had some very good chances, and then scored the goal in the last minute.
"On the other side, I managed to make the team believe it can do it, and we were very close. We played many minutes of good football and we created the chances. We played very well in the first half."