Manchester United manager David Moyes is confident his side can launch a stern defence of their Premier League crown even if they fail to add to their squad in the summer transfer window.

While Chelsea and Manchester City have made a string of additions this summer, United have so far failed in their attempts to make significant strides in the transfer market, making just the one signing in the form of Uruguay youngster Guillermo Varela.

Moves for both Thiago Alcantara and Cesc Fabregas have failed but with United seemingly running out of options, Moyes has hinted his pursuit of new additions may relent, claiming his current squad is good enough to start the new campaign.

"Well that's the squad that finished 15 points clear top of the Premier League," Moyes said. "The squad Manchester United has got without any additions will be tough opponents for any team this year.

"I never said at any time that I knew that we would get him (Fabregas). We've made offers that were rejected and we'll take stock of the situation and see where we go from there."

In Moyes' first season in the Old Trafford hot-seat United will face an instant test of their title credentials with games against Chelsea, Liverpool and Manchester City in the first two months of the season.

Entwined with the start of the club's Champions League campaign - relative unchartered territory for Moyes - the opening weeks of the new term represent a daunting task for the new manager.

A challenge made all the more difficult by a pre-season injury crisis which sees Wayne Rooney, Nani, Antonio Valencia and Nemanja Vidic all training away from the first team squad back at the club's Carrington training base.

Captain Vidic will return in the friendly against Crewe Alexandra on Monday while United conclude their Far East tour against Kitchee FC, seeking just their second win of the trip before they return home.

United face AIK Fotboll in Stockholm on 6 August, a game in which Rooney is expected to return following a hamstring problem, prior to the last game before the start of the Premier League season against Wigan Athletic in the Community Shield.