Less than two weeks after the end of a season that saw Manchester United restored as Premiership champions, manager Sir Alex Ferguson has sent a chilling message to the whole of Europe: "That was just for starters. We're  going to get even better next season."

While most clubs are still sorting out their shopping lists, United have set the big-money market alight by splashing nearly £50m on three players, with the promise of even more to come.

They have agreed deals in principle for two of the most sought-after players on the continent in 20-year-old Sporting Lisbon wonder winger Luís Carlos Almeida da Cunha, better known as Nani, and 19-year-old Brazilian  midfield maestro Anderson from FC Porto for an outlay reported to be in excess of £30m. This follows swiftly on the deal they have completed with Bayern Munich for Owen Hargreaves who is set to join the champions for a fee of £17m.

Indications are that United's spending will not stop there. It is expected that several fringe players may be on the move from Old Trafford in an effort to balance the books, but Fergie has been given the green light to sign the players he feels are needed to not only retain the Premiership title next season but make a determined assault on the Champions League.

He has made it known that he wants a striker, and the names of Samuel Eto'o (Barcelona), Fernando Torres (Atletico Madrid) and David Villa (Valencia) have all been linked to United.

But it's the signing of Nani and Anderson, and the swiftness of the deals,  that has stunned Europe, and much of that is down to Carlos Queiroz, Ferguson's No.2 at Old Trafford, and chief executive David Gill, who brokered the deals with both clubs in Portugal, leading to an announcement on the club's website. Queiroz's part was crucial as he is a good friend of agent Jorge Mendes who, coincidentally, is Cristiano Ronaldo's agent.

Portuguese international Nani had been linked to a deal with Tottenham and has been dubbed the new Cristiano Ronaldo. However, after losing out to Spurs in the race to sign Gareth Bale, it seems United would not be beaten this time around for a player who they see as Ryan Giggs's long-term replacement.

Brazilian starlet Anderson (full name Aanderson Luis de Abreu Oliveira) dazzled in the Portuguese championship this season, helping Porto to clinch the domestic title. The 19-year-old has become one of the most sought-after young talents since being crowned player of the tournament in the 2005 FIFA Under-17 World Championships. He has been likened to compatriot Ronaldinho, and despite strong interest from Barcelona and Chelsea, United have agreed an undisclosed fee with Porto for his signature.

A statement on United's website read: "Manchester United is delighted to announce it has agreed terms in principle with FC Porto and Sporting Lisbon for the purchase of registrations of Anderson and Nani. Personal terms have been agreed and a formal announcement will take place once the necessary administrative procedures, including medicals, have been completed."

Much to the surprise of United fans who protested at the club's takeover two years ago, it seems that the Glazer family are digging deep to finance United's continuing quest for success. Depending on progress, both Anderson and Nani could cost United £17m each, already nearly double what they spent on the single transfer of Michael Carrick last season.

Of course, there are expected to be some departures to make way for all this spending, with Gabriel Heinze rumoured to be leaving for Spain and other fringe players being allowed to go. But Ferguson is clearly focused on strengthening his squad, and these captures serve as a clear warning to all their rivals that United will be even stronger next season.