Former Real Madrid  defender Ricardo Carvalho believes Cristiano Ronaldo  will renew his contract at the club and warned him that those who leave always regret it.Ronaldo's contractual situation at Madrid has hogged the airwaves this summer as speculation grows he would accept a move back to former club Manchester United.But Carvalho, who recently signed for Monaco, has backed the los Blancos icon to put pen-to-paper on a deal to extend his stay at the Santiago Bernabeu beyond 2015."Every player who has quit Real Madrid will have regretted it later," the 35-year-old underlined to A Bola. "Cristiano will renew his contract."Cristiano is a winner, he always wants to play and win and that’s why I am in no doubt that he will continue with Madrid."Carvalho also waged into the debate over whether Ronaldo is a better footballer than Barcelona star Lionel Messi and, as a compatriot and a former team-mate, the Portuguese defender unsurprisingly rates the Madrid attacker higher."Cristiano is a more complete player than Messi and I am not just saying that because I am Portuguese, looking at it objectively, it’s what I think," he said.Asked about wantaway Madrid full-back Fabio Coentrao's status, Carvalho replied: "I think that he wants to move on because he thinks that it would be the best thing for him to do career-wise."Personally, I think he should continue because he meets Madrid’s requirements. He played well in practically every game last season. "He’s a great left-back, to the point where he even made a few of his critics change their opinion about him. I do think that he has a place at Real Madrid."