The pair are part of the Spain squad due to face England at Wembley.
Reina said: "Playing in England has certainly helped him. It has made him a regular starter for Spain.
"He's up there with the best in the Premier League. He has improved since he came to England, just like Xabi Alonso and Fernando Torres did when they joined us at Liverpool and just like Juan Mata will do at Chelsea.
"It helps you become a better player playing in a different league."