Manchester United star Wayne Rooney is aware the club have a point to prove this season following the departures of Cristiano Ronaldo and Carlos Tevez.
The Red Devils have sold Ronaldo to Real Madrid in a world-record deal, while Tevez's loan stay ended and the Argentine joined rivals Manchester City.
Critics have suggested that United are now fighting an uphill battle to record a fourth Premier League title in a row in the wake of the summer exits.
Rooney knows the doubters will be ready to pounce if success is not achieved this season and the striker is determined to ensure that does not happen.
He said in The Sun after scoring in United's 1-0 win over Birmingham on Sunday: "We have to prove to everyone we can win this league again.
More to come
"We played well in parts against Birmingham, but there is more to come from us.
"It was the first game of the season and it's always very difficult after playing a lot of games pre-season.
"When it comes to the atmosphere and intensity of the game, it's a lot quicker than pre-season games."
Rooney's winner at the weekend came on the back of a strike against Chelsea in the Community Shield to take the England ace to 99 goals for his club.
As the 23-year-old closes on a century of United goals, he is revelling in a central role after being played on the flanks during Ronaldo and Tevez's time at Old Trafford.
Foster aim"I'm pleased with two in two," he added. "I'm enjoying my football and the manager has said he's going to play me down the middle, so I'm looking forward to that."
Meanwhile, goalkeeper Ben Foster hopes he can keep Edwin van der Sar out of the United side when the Dutchman returns from injury.
Foster said: "I was happy with my contribution on Sunday. This is my big chance while Edwin is out.
"I just have to do what I can and hopefully when he comes back I'll have done enough to stay where I am."