Both men got on the scoresheet yesterday as Manchester United eventually cruised to a 4-0 win over West Brom at Old Trafford.

While Berbatov's languid style does not fit the fast-moving United stereotype and completely at odds with Rooney's all-action approach, the pairing is starting to pay dividends, as Sir Alex Ferguson always knew it would.

But the Bulgarian knows it is not the finished article just yet, which means defenders might really have cause to worry in the weeks and months that lie ahead.

"Our partnership is progressing well," said Berbatov.

"You can see it on the pitch. We have been working in training to try and understand each other and it is working. The result was really good."

Although Berbatov gives the impression of being totally unconcerned about anything, he was desperate to score his first goal at the Theatre of Dreams since his deadline-day move from Tottenham.

It duly arrived at the end of a 15-minute purple patch for United in which the hope West Brom had slowly been building throughout a goalless first-half evaporated.

Rooney started the romp.

As it is October, he could afford to adopt a phlegmatic approach to Mark Halsey's decision to disallow a first-half effort for a foul on Gianni Zuiverloon.

Amazingly, Rooney has now scored 17 goals in the last 12 appearances he has made in the month of his birthday - and there are still a couple of weeks to go.

He netted for the sixth successive game when he collected Berbatov's short pass, cut inside Ryan Donk, then fired neatly past a previously unbeatable Scott Carson.

"I am really enjoying it at the minute," said the 22-year-old.

"I don't know why I go on these scoring runs but I will just carry on playing the best I can, hopefully the goals will keep coming and I can help the team win."

To prove he is not just a master of scoring goals, Rooney also set up Cristiano Ronaldo, then provided substitute Nani with the easiest of tap-ins a minute from the end.

Ferguson, while delighted at Rooney's recent form, is mindful of the superlatives likely to follow given it is barely a month since questions were being asked about the former Everton man's place ahead of Carlos Tevez in the United pecking order.

"We are delighted with Wayne," said Ferguson.

"We know about his ability and now he is maturing, as all young players do.

"They get better each year. The training standards are high, the expectations from our staff are high and the expectations of the players are high so it is a natural progress.

"But I don't think it is the best he has played. He just has a drive and energy about him which is refreshing.

"I know there is this English thing to look upon Wayne Rooney as the saviour of English football but he is part of a team. As good as he was, there were others just as good."

The result, even though it could cost United the services of Patrice Evra for Tuesday's Champions League showdown with Celtic after he picked up a tight hamstring, was a perfect response to the performances of Chelsea, Liverpool and Arsenal who all, in different ways, registered impressive victories.

"We won the league last year and we won the European Cup," said Ferguson.

"The other teams know about our quality and we know about theirs. Any one of the four teams could win the league. It is important for us to look after our own game and keep doing the right things."

Ferguson confirmed both Anderson and Carlos Tevez will be available for the Celtic game but had not been considered for the weekend given the timing of their respective arrivals back in Manchester following midweek World Cup duty in South America.