Kaka has admitted that he has flopped in his debut season for Real Madrid.
With Madrid still locked in a tight battle with Barcelona for the Primera Division crown, the Brazilian playmaker has conceded he could have played better this season, but blamed injuries for his failure to settle into the side.
''I'm not happy with my performance, but my problem is physical,'' he said. ''I have suffered a lot since I arrived.''
Kaka made a goalscoring return to the Real side last weekend, grabbing the winning goal against Real Zaragoza eight minutes from time. It was his first goal since the Champions League defeat to Lyon in March.
Kaka denied sustaining his troublesome thigh problem in that match, saying it happened in training subsequently.
''I was not hurt in the game,'' he said. ''It was the following Saturday when I hit the ball I felt pain.''
The injury was slow to heal, leaving Madrid fans increasingly frustrated with a player who had already received boos for his sometimes lacklustre displays.
Kaka was briefly made the most expensive player in the world when he signed for Madrid for €68.5 million last summer, only for his new club to break the record weeks later by signing Cristiano Ronaldo.
While Madrid's exuberant spending spree has improved the squad and puts them in a battle for the title with Barcelona which is set to go down to the wire, fans were hoping Kaka would have a bigger impact and the 28-year-old has not been surprised to hear boos.
''I heard them in Sao Paulo, and Milan, and now here,'' he said. ''The fans are very emotional, and if things do not go as they want, the big-name players suffer. But I will bring them joy.''
Kaka's sole focus now is to help Madrid catch Barcelona, who are only one point ahead with four games left.
''We've got a great chance to win the league,'' he said. ''We think we can do it. A point is not much to overcome and we want to win all four of our remaining games.''