With Didier Drogba, Nicolas Anelka, Salomon Kalou and Andriy Shevchenko in their striking ranks, Chelsea own one of the most exciting, powerful and experienced attacking line-ups in world football. And complemented by the offensive starlets of Deco, Florent Malouda and Joe Cole, who themselves sit in front an immensely strong central midfield duo of Frank Lampard and Michael Ballack, means they have world-class ammunition lethal enough to fire any club down on their day.That is the proposition that Manchester United are up against this season in their quest to regain both their Premier League and Champions League titles. They faced similar dangers from their fiercest competition in the last campaign and overcame them to great success, albeit by only two points in the league and by one penalty in the European Cup. The Portuguese threat of Deco was not against them then, but him aside and Sir Alex Ferguson’s men triumphed over their London rivals quite emphatically on all fronts.Whether they can reproduce their glory this season remains in considerable doubt though, despite the fact that there have been no significant departures from the club and, other than Deco, no arrivals of the same magnitude to Chelsea. Both squads remain almost parallel to the level of quality that they were last season, and that is likely to be reflected in another tight and hard-fought battle between the pair on all fronts.The two clubs have been in the media spotlight for very different reasons throughout the summer months, and there is no doubt that the extra attention afforded to Chelsea was welcomed much more by the club than the added interest on Manchester United. Whilst many column inches were expectedly filled when Luiz Philippe Scolari became the new manager of former, the latter’s desperate attempts to resolve the ongoing Cristiano Ronaldo transfer saga caused unwanted debates and discussions from all corners of the nation and beyond. Sir Alex Ferguson was forced to fly to Portugal just to restore the player’s faith in the club, and for the time being turn his head away from the mouth-watering prospect of playing for his dream team Real Madrid.And whilst Ferguson’s actions have succeeded in convincing Ronaldo to stay at Old Trafford for one more season at least, the uncertain cloud which hung over the club disrupted the pre-season focus somewhat. Ronaldo is not fit to start the new Premier League campaign on Sunday against Newcastle, but when he does return to action in around two months time his every move will be closely watched and scrutinised by fans and the media. How commited he really is to the club is still in some doubt. We will soon find out the answer though.With fewer attacking options at the beginning of the season, United have been left well short of the quality possessed by Chelsea in that area of the pitch. At his age Ryan Giggs can now only take part in a limited number of games, and Paul Scholes is walking along the same path gradually. Nani is still learning but can produce moments of explosive brilliance, whilst the team lack attacking drive from the centre of the park. United managed to achieve truly special things last season with these same problems, but whether they can pull off the same feats this time around is still a mystery. At least they began the season in the same vein as the last with a penalty shoot-out victory in the Community Shield match on Sunday.The biggest problem for United is their strikeforce, and Wayne Rooney’s untimely virus means that Carlos Tevez must lead the line alone in the opening matches of the new campaign, unless Ferguson feels young prodigy Frazier Campbell is ready for first-team football. This will happen only if the club do not sign a new forward before the end of the transfer window on the last day of August.A quality accusation in this area is a must for Ferguson if he is to feel fully confident of his side regaining their domestic crown. With Tevez, Saha (who is always injured and is expected to leave very soon) and Rooney as their only three senior strikers, a fourth would be much welcomed. The current pair offer hard-work, endeavour and great skill at times, but neither act as a target man of any sorts to the rest of the team. Rooney prefers to sit deeper than the regular forward, so playing him up front on his own is almost suicidal, whilst Tevez is also more of a creative player rather than somebody who likes to lead the line. United have lacked this kind of individual ever since Ruud Van Nistlerooy left for Madrid, as Louis Saha has been injured for so much of his time at the club.Tottenham star Dimitar Berbatov has been heavily linked with the club, and seemingly wants the move to go ahead himself, and Valencia forward David Silva has recently been courted by the manager too, though the Spaniard says he wants to stay in his native country rather than move abroad. It appears that Berbatov would be the best option for United, although his services could prove expensive. He oozes class though, and his exceptional touch, control, technique and finishing ability would help the team so much in their push for silverware.A significant signing of Berbatov’s level needs to be made this summer by Manchester United if they are to be anywhere near as strong as Chelsea in the offensive department, but with this new addition Ferguson’s men could well march on to yet more glory in this coming campaign.