Ronaldo will win his 100th international cap against Michael O'Neill's side on Tuesday, searching for his 38th goal in Portugal colours.
Fulham centre-back Hughes has insisted that he is prepared to face the Real Madrid talisman and is well aware of the task at hand.
He told reporters: "I have played a handful of times against him but maybe he has gone another level since his days in the Premier League, and maybe he can go further.
"He has gone and become just as successful in Spain and maybe there's more to come from him. I don't think he has peaked, believe it or not. He is still going and appears to be getting better.
"The best players play at that level every single night whether it is the first game of the season, a windy night in November or the Champions League, it is just their way."
Ronaldo has 14 goals in just 11 club matches so far this season, including a brace at the Nou Camp in a memorable 2-2 draw against Barcelona.