Fulham boss Lawrie Sanchez believed a poor decision to allow Yakubu's first goal cost his team in their 3-0 defeat to Everton at Goodison Park.
Fulham held Everton in a goal-less first-half of few chances, but then Yakubu put the Toffees in front in the 51st minute when he netted the rebound after Antti Niemi did well to save a Tim Cahill volley.
But Sanchez believes Cahill was off-side and by allowing this first goal when the game was finely poised, it cost his side.
Sanchez said: "I thought we were very good first half, probably edged it, we had more opportunities, looked more likely to (score).
"Goals change games basically. Everton got their first goal, fortunately I think, and thereafter poor marking from a set-play (made it) 2-0.
"We were chasing the game after that as we had to and it allowed Everton to perhaps open us up a little bit and Yakubu gets the third one, (a) good goal from him."
The Fulham boss believed Tim Cahill was off-side in the lead up to the first goal.
"I think when you see it, it will be self evident," he said, adding: "For the first 45 minutes we came here, we did very well, caused them all sorts of problems. We need to score the goal when we are on top and when we are pushing.
"We didn't get the goal, they did and it changed the whole complexion of the game. We were a shadow once they got the second one."
Fulham have not won away this season and Sanchez said: "It is something we obviously need to put right. We need to get some wins on the road.
"I thought at half time, excellent again, an excellent first half performance, now let's go and build on it.
"We didn't and ultimately we've got beaten 3-0 and it is very disappointing. We are all very disappointed in there.
"But football is a moving feast and we now come home to Newcastle next week, we come home to Newcastle and Wigan, two crucial games for us and we have to get points, there is no two ways about that."