The French defender, 19, has played more often than was expected and has seen coach Jose Mourinho declare him a bigger talent than Laurent Blanc at the same age.
"Choosing to sign and go to Real Madrid looked like it might be a suicide mission, but I knew where I wanted to go and why. I never doubted myself," said Varane, who chose Real over Manchester United last summer.
"What made the difference was that the Portuguese coach (Mourinho) said he wanted to work with me. This and the guarantee of progress in my training at such an important club were instrumental in my decision."