Cristiano Ronaldo warned against Real Madrid exit
The 28-year-old has been linked with a summer return to Manchester United, but Karanka insists that Ronaldo and Madrid are "good for each other".
"He will keep getting better. Here is the ideal place and for Real Madrid it is great to have him," said Karanka.
Ronaldo scored his 200th goal for Real in a 6-2 win over Malaga on Wednesday.
The Portugal international has reached the mark in just 197 games and his celebration, slapping the badge on his shirt and pointing repeatedly at the Bernabeu turf, was interpreted by some as an indication that he would stay beyond the end of this season.
Ronaldo said in January that he would wait until his contract expires in 2015, but was unsure where his career would take him after that.
He has since been linked with a return to Manchester United, who he left in an £80m move in July 2009 and with whom he had an emotional reunion in the Champions League in March, as well as French league leaders Paris St-Germain.
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