The Clarets fell behind to Jean Michael Seri's early long-range strike but equalised 10 minutes later via Jeff Hendrick.
Dyche admitted after the game that Fulham were superior to his side, and revealed that defending will be a source of focus for him in the coming weeks.
"They were the better side," Dyche told Sky Sports News. "More inventive, more productive and possibly signs that their £100m has been spent well it seems on that performance.
"We huffed and puffed our way back into the game, we have a spirit and a belief and demand in the players and they've at least got themselves back in it at 3-2. We had some moments, so did they, but realistically over the whole game, they were the better side.
"We conceded two sloppy goals. We don't normally do that, we had a couple against Watford as well, so that's something we've got to look at and tighten that side of things up. It's tough then.
"They're a good side and I was impressed with some of their football, we knew that from last season. The difference was their centre-forward (Mitrovic), I thought he was the best player on the pitch by a long shot. At the end of the day, our performance wasn't up to where it needs to be and theirs was."
The Clarets extended their winless run in the league to eight matches with defeat in London, and have now conceded 10 goals in their past three in all competitions.