The Manchester United forward has now scored eight goals in six games following his strike in the 4-0 win. He also collected two assists as Portugal pair Cristiano Ronaldo and Nani added their names to the scoresheet, along with Dimitar Berbatov.

And, with Celtic due in the Champions League on Tuesday, Rooney admitted he was at his peak.

"This is possibly the best form of my career," said Rooney.

"Everything is going well for me at the moment. Hopefully that can continue and I can help this team win even more trophies."

Rooney's efforts helped eclipse a disappointing opening period for the Red Devils, who dominated throughout but drew a blank as referee Mark Halsey ruled out what appeared to be a perfectly good goal from the England man for a foul on Gianni Zuiverloon.

"From the position the referee was in, I can understand why he didn't give it," said manager Sir Alex Ferguson.

"Wayne did have a hand on the lad's shoulder but he did not pull him. You can see it from the TV replays but obviously the referee does not have that advantage."

A capacity crowd did not need to look again to see the damage Rooney could cause.

Following his World Cup qualifying exploits for England, Rooney carried on where he left off, collecting Berbatov's short pass before slotting in a fine solo effort that ended the brave resistance of West Brom keeper Scott Carson.

"Wayne is only 22," said Ferguson.

"We expect him to improve, as we did with Ronaldo.

"But he is a member of the team, just like everyone else."

Ferguson does feel his side are now starting to find their feet after a difficult start to the campaign.

For the first time, they have joined Chelsea, Liverpool and Arsenal in the top four, from where Ferguson is convinced the champions will emerge.

"I don't think we have given them a warning tonight," said Ferguson.

"I think we provided that before the season began. We won the league last year - and the European Cup.

"Those three teams know the quality in our side, just as we know the quality in theirs.

"It is a fantastic league and any one of the four could win it."

Ferguson did confirm Patrice Evra is a doubt for the Celtic game after going off with a tight hamstring, although that did little to dampen the enthusiasm of a fifth straight win.

The final scoreline was a harsh judgment on West Brom's battling qualities, although it did not surprise Tony Mowbray.

"That is what can happen in matches like this," said the Baggies boss.

"We are coming up against teams who can spend £30million on strikers, which is where it matters.

"There is no shame in the result for us. Wayne Rooney is a world-class player - and they have five or six of them."