"The defending today was not good enough at this level and when you give away goals like we did today against Fulham it turns into a frustrating day.
"We've just got to take the flak that comes our way and make sure we're better next week at Bolton."
Sunderland went into the game on the back of four defeats in five matches and their hopes of turning things around were not helped by an ever-growing injury list that left them without a recognisable striker to call on.
Benin international Stephane Sessegnon, a midfielder, had the job early on, and Sunderland finished with defender Nedum Onuoha sent up front, but the most glaring in a collection of Sunderland misses came from Lee Cattermole.
Bruce said: "We've had a horrific problem for the last two or three months with injuries and that was shown again today. We've had many things stacked against us."
Fulham boss Mark Hughes saw his team register only their second away win of the season in the league, and their first at the Stadium of Light since 2002.
He was particularly enthused by the performance of Philippe Senderos.
The Swiss defender, who was signed in June, played in the World Cup but tore his Achilles tendon in his first training session in west London.
Saturday was Senderos's first appearance for the club, and after an understandably tentative start he coped well.
"The most satisfying performance was from Philippe," said Hughes.
"He's coming back from a really long injury, and he played really well. It's been a long road back for him."
Reflecting on Fulham's overall performance, Hughes added: "We weren't as good as in our previous two matches but we got the job done.
"The first half, although we got the lead, we could have played better than we did; the second we took the game away from Sunderland."
Source: BBC Sport
Source: BBC Sport