A lot of chants have been heard at Blackburn games this season and one of the most frequent has been "feed the Yak and he will score". Twelve goals in 13 league starts, including two against the champions on Saturday, is a formidable return for a striker who cost only £1.5m.
Yakubu has been a slight enigma since arriving in England, never really settling fully at a club, never looking either fully fit or particularly athletic.
Now he is playing regularly for Rovers, filling a demanding role as the sole front man, demonstrating his eye for goal and unerring ability from the penalty spot. Few convert penalties with such conviction as the Nigerian. Naturally confident, Yakubu has instilled a sense of belief in the brittle Blackburn mind-set.
"I always believe I can score goals no matter what team,'' reflected the former Everton, Leicester, Middlesbrough, Portsmouth and Maccabi Haifa forward. "When I am really fit I can score goals.''
Yakubu was one of the bigger earners at Goodison Park yet there was some surprise he was sold, following a prolific loan spell at Leicester, as Everton had struggled for goals.
"In every two games he will pop in a goal,'' said Blackburn manager Steve Kean. "So our challenge is to make sure we don't burn him out and we protect him from himself, because he wants to play in every game.
"He is at his best, physically. He is sharp and knows he is going to start games and is getting to know his team-mates and the type of service he will get. If we can give him the service and keep him fit -- and we are very big on sports science -- he will continue to do well."
As against the champions. United's defence was shaky, with injuries forcing them to start Michael Carrick at centre-back, but they still had Phil Jones in there.
Yakubu charged around, using his energy intelligently by timing his runs to greatest effect. He swept Blackburn into a two-goal lead as complacency appeared to stymie United.
Good players badly underperformed. Nani gifted possession away. Alex Ferguson's tactics hardly helped, starting with Rafael in midfield, although he rejigged his side at the break, pushing Antonio Valencia on successfully.
Dimitar Berbatov scored twice, setting up what should have been the classic trademark United finish, but the life again drained from them.
Blackburn, exploiting poor keeping by David de Gea, seized all the points through Grant Hanley, who joined another youngster Adam Henley in shining.
On a greatly encouraging end of year for Rovers, Kean could have Gaël Givet back for today's test against Stoke City at Ewood Park.
Yakubu believes the win over the champions will change the fans' negative perception of Kean.
"It has to,'' said Yakubu. "We as a team always believe, all the players celebrate with the manager when we score. Look at the way he believes in the players. He never puts pressure on the players, even when we are losing. He believes in us.
"He tells us 'enjoy yourselves', 'give everything'. The players are playing for the manager and playing for the club.
"They (the fans) should give him a break and support the team. Playing at home, when we go down, it is 'he has to go, he has to go' but things have really changed.
"We are looking forward to the next game and hopefully they can get behind the team. We will be fine."
Yakubu had special praise for the youngsters in the team.
"These players want to play; no matter what age, the Premier League is a great league to play in. All around the world people are watching. Give credit to Adam (Henley) who played left-back, it is unbelievable. Every game he plays he is getting more confident," he said.
The trick for Rovers now is to maintain the surprising momentum acquired from four points in two difficult games. "Nobody gave us a chance in these two games at Anfield and Old Trafford,'' said Kean.
"I hope this does change the atmosphere for our home games because we want to climb the table. I have five or six players under 25 and if they can feel a negative vibe around the ground it can get to the younger players.
"Not so much the senior players because they have been round the block and can block it out of their mind. I hope the fans realise we have a young side and are a little bit fragile and I hope they get behind us."
He urged the supporters to back the club through "thick and thin", adding: "What they will see is the lads giving it everything. I wouldn't imagine any true supporter would want to see us get relegated. I wouldn't class anyone who comes to any game wanting to see us lose as a supporter."
Asked to sum up in three words a year which has brought victories over teams such as United and Arsenal but barracking from his home crowd, Kean replied: "I think it would be one word -- rollercoaster."
And one important name -- Yakubu. (© Daily Telegraph, London)