Blackburn boss Steve Kean was delighted with the response of his team as they recovered from a 7-1 defeat by Arsenal last week to beat Queens Park Rangers.
Yakubu, Steven Nzonzi and an own goal by Nedum Onuoha gave Rovers a blistering start to the game - Jamie Mackie's brace pulling it back to 3-2.
"The fact we had done so well in the first half managed to give us a very good lead," Kean told BBC Sport.
"And it put to bed the performance at Arsenal which was under-par for us."
Victory means Kean's side remain in the Premier League's bottom three but they are one of five teams at the bottom separated by two points.
But, once Yakubu hit the crossbar early in the second half, QPR improved and Mackie's goals meant the hosts were hanging on towards the end as they secured their fifth win of the season.
"We felt we let ourselves down in the Arsenal game," Kean added. "We've worked ever so hard all week at the training ground on the defensive side of the game in giving us a platform to go and get the chances.
"In the first half we were exceptional and I said to the lads at half-time we have to beware because there was no way they were going to come out and let us steamroller them in the second half.
"Yak's chance - when he clipped the bar to go to four up - was a turning point because then QPR started to be more offensive. I did feel we had a little bit of wobble. But we had some young players on the pitch and we got there in the end.
"The work-rate and determination in the first half display merited the three points."
Yakubu, who served a three-match ban after being sent off against Fulham last month, scored his 14th of the season.
And with key defenders Gael Givet suspended and rumours about Chris Samba's future, Kean was under no doubt as to his top scorer's importance.
"Since Yakubu has been here with us, he's scored all types of goals," Kean said. "He's got every type of finish in the book and we know if we get him the service he will produce.
"We are disappointed he didn't get that one that clipped off the bar."
QPR boss Mark Hughes was disappointed by his side's first half display, as they slipped to their third Premier League defeat in his five games in charge.
But he was encouraged by the second-half reaction of his players.
Hughes told BBC Sport: "In the first half we hold our hands up, that wasn't acceptable and it certainly wasn't what we anticipated.
"The guys came out in the second half and understood exactly what I demanded of them and they had a real go.
"They showed real belief and desire and did the hard yards that you have to do to get back into Premier League games and could easily have got back on levels terms. But you cannot give any Premier League team a three-goal head start."