MADRID: Kaka has insisted that there will be no rivalry between himself and Cristiano Ronaldo, Real Madrid's two newest galacticos.

Speaking at his official presentation at the Bernabeu, the Brazil international maintained that he is looking forward to playing alongside Ronaldo and that the players will be "compatible".

He said: "There will no problem between us, either on or off the pitch. It's a great privilege to be able to play with great players, not only with Cristiano Ronaldo but also with Raul Gonzalez and (Iker) Casillas."

However, he warned that Real's spending spree will not guarantee success, despite returning president Florentino Perez spending well over a £100 million (S$238 million) on star players.

"Having talented players is positive, but they must work hard and make sacrifices to win titles," he cautioned.

Indeed, the capture of the last two winners of the Fifa World Player of the Year awards marks the return of the controversial galacticos era to Madrid, with Perez also splashing out huge fees on big-name signings such as Zinedine Zidane, Luis Figo and David Beckham during his previous tenure in charge from 2000 to 2006.

That policy reaped indifferent rewards when, after an initial period of success, Real failed to claim a trophy in the final three years of Perez's reign.

Kaka, who has penned a six-year contract and has cost Madrid a reported £56 million, was greeted by a crowd of more than 40,000 as he was unveiled by Perez and honorary president Alfredo di Stefano.

He will be joined next week by Ronaldo, with the Portugal international being presented next Monday after completing his world-record £80 million switch from Manchester United.

Meanwhile, United have signed Ecuadorian winger Antonio Valencia from Wigan Athletic on a four-year contract for an undisclosed fee.

The 23-year-old joined United as a replacement for Ronaldo.

"Playing in front of 76,000 fans alongside players like Wayne Rooney, Rio Ferdinand and Ryan Giggs will be an amazing experience. I can't wait to get started," Valencia said on United's website.

- AGENCE FRANCE-PRESSE, REUTERS