They might not have filled the gap left by the world's most expensive player with a world-class replacement, but don't be fooled, United will be challenging for honours at the end of the season.
Even without the influence of Cristiano Ronaldo, Sir Alex Ferguson has one of the strongest squads in the league at his disposal and, more importantly, the Scot has the experience and the respect to carry the club into their next challenge.
The team were always going to struggle to emulate their European double winning success of 2008, but still managed to pick up their third straight Premier League title, along with the League Cup, last season and will be in a strong position to continue their trophy haul in 2009-10.
United's ability to bounce back from adversity is the attribute that sets them apart from other clubs. After a potentially damaging defeat to Arsenal in November, a run of 14 consecutive league games without conceding a goal - with Edwin Van der Sar setting a new clean sheet record of 1,311 minutes behind a defence that was not always settled - put them right back in contention for the title and had pundits purring over their 'untouchable' status.
Later into the season, when they were hammered 4-1 at home by Liverpool and lost the following game 2-0 to Fulham, United rallied behind a couple of inspirational performances from 17-year-old Federico Macheda and brought home the title with eight wins in their last nine games. No team in history is as clinical when it comes to the pressure cooker of the final weeks of a season.
However, this year they have a new problem to overcome. Unquestionably, the squad is weaker without the talent (and goals) of Ronaldo and Carlos Tevez and it would be churlish to suggest that two players of such immense talent will not be missed.
Ronaldo brought an unprecedented number of goals from midfield as well as numerous assists, free-kicks and a presence that would strike fear into the most experienced of opposition defenders. One could argue that United may be better off without the Portuguese's off-pitch antics blurring the club's focus, but on the pitch he is simply irreplaceable.
Tevez may be less of a loss - especially if you believe Ferguson's quotes after his move to Man City - but the Argentine was still a great option to bring off the bench and contributed some key goals in the latter half of the season. His tigerish work-rate made opposition players work harder and United do not have the luxury of such a talented substitute for the coming season.
A lot of the pressure to fill the void will fall on the shoulders of Dimitar Berbatov and Wayne Rooney. By his own high standards, Rooney has been subdued - failing to break the 25 goal barrier - and has been overshadowed by the talent of Ronaldo in recent years. Now is his time to shine and the England striker could benefit from the freedom of playing without the Portuguese around; while Berbatov will have the added responsibility of leading the line alongside him and will certainly be expected to net more than the nine goals he managed last term.
Ferguson will also be able to call on Macheda again - although the youthful striker has lost some of the 'unknown' characteristics that may have given him the jump on his opponents - but the Italian teenager will probably be beaten to the role of 'super-sub' by Michael Owen.
The former Liverpool and Newcastle striker shocked the world when he signed for United on a free transfer, but hit the ground running during the club's pre-season tour of Asia and the signs are that he could prove to be a useful player for Fergie if he can maintain his fitness levels. A target of 15 Premier League goals should represent good value, but it would not be much of a surprise if he spent a large part of the season in the treatment room after a number of years in injury hell.
Ferguson's other summer signings, Antonio Valencia and Gabriel Obertan, will also bear the responsibility of scoring but more importantly, creating, goals. Comparisons with Ronaldo are more likely to follow Valencia because of his style of play, but the Ecuadorian winger is a relatively experienced midfielder for a 24-year-old, while Obertan will be given the luxury of time as he is a raw 20-year-old with potential to impress further down the line. Still, United fans would probably have wanted to see a David Villa, Franck Ribery or Karim Benzema arrive.
The beauty of United is that no single player will have to shoulder the burden though, as they have tremendous squad depth. Almost every single player at the club could walk into some of the other Premier League sides and Ferguson has built his reputation on keeping his squad players happy. The likes of Rooney, Ronaldo and Rio Ferdinand may take the headlines, but it is the grafting players like Wes Brown, Darren Fletcher, John O'Shea and Jonny Evans that keep the club in the hunt for trophies on all fronts.
With club stalwarts Paul Scholes, Gary Neville and Ryan Giggs coming to the end of their careers, Ferguson has had to rely more and more on his backup players, but also has faith in his youth stars. Giving Rafael da Silva a chance to shine at right-back, the new season should also provide opportunities for Darron Gibson, who has impressed more than his teammates when given a spot in the side. Using the Carling Cup as a springboard, Gibson heads the queue, but with Anderson also keen to impress there are three young players ready to step in when United's old guard step down.
In defence, the rise of Jonny Evans has allowed Ferguson to sleep easy if Rio Ferdinand or Nemanja Vidic are injured. The Northern Irishman will not take a starting spot unless one of the two best defenders in the league suffers a catastrophic loss of form, but is an excellent replacement along with the experienced and versatile Brown and O'Shea. While, in goal, the club have future England #1 Ben Foster waiting in the wings for Edwin van der Sar to relinquish the gloves. Foster will have his chance to shine in the early weeks of the season with Van der Sar injured.
So despite the negative light surrounding the departures of two of their biggest names, United are still well positioned to mount yet another charge to the Premier League title. With the league's best defence and Sir Alex keen to prove to the world that it was his squad that have brought him success over the past decade - and not one Portuguese winger - perhaps the greatest motivation of all is his desire to beat Liverpool's record of 18 league titles, which he tied last season. Write them off at your peril.