The striker looks set to miss a considerable amount of playing time for both club and country, with England set to take on Macedonia and Ukraine in early September, while United face off against Southampton, Wigan and Liverpool within the next month.

Coming off the substitutes' bench with just over 20 minutes remaining, a clash with Hugo Rodallega in injury time forced the England international to be stretchered from the pitch with a nasty cut to his leg.

Sir Alex Ferguson confirmed after the game that Rooney had been sent to hospital.

"It's a very bad gash - he's been sent to hospital and I think he'll be out for four weeks," Ferguson told Sky Sports.

"Rodallega followed through after his shot. Obviously it was an accident."

Fulham took the lead after just three minutes when Damien Duff latched onto Bryan Ruiz's free-kick.

United responded strongly with three first-half goals from Robin van Persie, Shinji Kagawa and Rafael - the former two with their first for the club.

A mix-up in defence between David de Gea and Nemanja Vidic saw the centre-back knocking the ball into his own net with 25 minutes still to play, but the west London outfit could not find the equaliser.

Ferguson was delighted with Van Persie's contribution to the result.

"It was a fantastic finish from Van Persie, absolutely brilliant," he said.

"That typifies the goalscoring ability he has and it really lifted the place - we played very well from that moment.

"I'm pleased for both him and Kagawa. It's still early doors for them, Robin has not really played with the team much and this was his first real game and that will get better."

Fulham boss Martin Jol, meanwhile, was disappointed with his side's mindset after they scored the first goal, suggesting they had been intimidated by leading at Old Trafford.

"We're a football team and if we do that we can control games, even away from home against United, and that was why it was unacceptable for us," Jol said.

"Maybe we were too modest, maybe because of the size of the club.

"But in the second half we promised ourselves that we would play the football we can play and that was a lot better, and I have to say I enjoyed the second half."

Meanwhile, Jol said he was ready to welcome back want-away striker Clint Dempsey.

"I am not a person who would not forgive a player because I left them last year and I have not seen them much this year," Jol said.

The United States international has been linked with a move to Liverpool throughout the offseason, and Rodgers was quoted as saying "Clint is a player we've inquired about" on the website of Liverpool's owners.

But Jol is determined to find a solution.

"I think there could be a resolution if Dempsey wants to stay," Jol said. "What can I do?

"I can't send him to the non-league or put him on loan at Stevenage or something. I would love to keep him and just sit down with him.

"Maybe something will happen in the next week."