Magath's men rounded off a miserable campaign on a high as substitute Chris David's superb last-gasp leveller secured a 2-2 draw with Crystal Palace on Sunday.
Fulham's relegation had already been confirmed last week, after a 4-1 defeat at Stoke City, and Magath was quick to criticise his team's lack of resolve.
"We have here a problem in this season, I think there were too many changes, there were three managers in one season and every manager, except me, brings his own players into the team," Magath said.
"The problem was we had no team which really identified with Fulham, that was a big, big problem.
"If you loan players in January, if you have a full team and bring in eight new players, it cannot fit.
"We never fight as a team which fights against relegation. I'm sorry to say such things, if I look at the television and I see Sunderland or Norwich playing, there was much more fight.
"I asked my team what's going on? And one was telling me 'we cannot fight.'"
However, the German - appointed in February following the departure of Rene Meuelensteen - was pleased with his side's display against Palace, and hopes that Davis' stunning strike can set the tone for next season.
"I was very glad that Chris David scored in the last minute and (could) make the result a little bit better for us and I think it was a sign for everybody that we are hopeful for the future," Magath added.
"Not only with scoring the goal but also with young players, that they step inside and play very well. For me, today, it was the start of a new season.
"We work now to come back. We have a lot to do and we will do so at the end. I think this goal will give our supporters this hope that it will be better in the future."
Magath also confirmed that Darren Bent and Lewis Holtby are to return to their parent clubs following loan spells at Craven Cottage.
"I think they go back," he explained. "They are not only loan players, they are players with high quality and high wages. We are not able to play such players, we are looking for young players."
