Former England defender, Ashley Cole, has said Cristiano Ronaldo is the toughest opponent he has ever faced. Cole revealed this on Monday after being inducted into the Premier League Hall of Fame. The fullback, who played for Arsenal and Chelsea, described Ronaldo as a complete footballer, who gave him nightmares on the pitch. Cole said: “Over the years, Cristiano Ronaldo and I had some mighty battles and we have a mutual respect for each other. “He came to the Premier League as a little bit of an unknown, but he soon understood what it took to be a top player. He was willing to learn and adap…