Wayne Rooney is fighting to get fit for Manchester United's opener against Newcastle, according to the Daily Mirror.

The striker sustained a hamstring strain during England's friendly game against Hungary at Wembley on Wednesday.

While Rooney has not been entirely ruled out of United's Premier League opener and has been undergoing intensive treatment upon returning to Old Trafford, his fitness remains a constant headache for Sir Alex Ferguson.

The 24-year-old has not just his fitness to recover from, but his goal-scoring touch as well.

Rooney has been struggling to shake off his World Cup form since he returned and has failed to find the net in United's pre-season games including the Community Shield.

United, last season's runners-up, will be hoping their star striker regain his fitness and form quickly as they seek to claim the Premier League title back from Chelsea, who have already got off to a flying start by beating West Bromwich Albion 6-0 in their opening match.