Kaka: "Barcelona" - the strongest opponent I have ever played against © EuroFootball.com

Real Madrid defender Kaka insists that there is no unbeatable opponent, although the results of their recent matches are much more favorable for the Catalans.

In an interview with "Band Sports," the 29-year-old Brazilian said: "They are definitely not unbeatable. After all, we won the King's Cup tournament final."

However, the footballer admitted that he has never played against a stronger opponent throughout his entire career.

"I think this is the strongest team I have played against, as they have assembled very well over a long time. In addition, Lionel Messi's self-confidence just oozes from the edges," Kaka said.

The defender also praised his teammate Cristiano Ronaldo, whom he considers a better player than Messi: "The Argentine has his strengths, but Cristiano has no weaknesses: he strikes with both his right and left feet, plays well with his head, and excels in set pieces."