The Arsenal manager feels that the Portugal star has made a phenomenal start to the season and argues that he now has the edge over his much-vaunted Barcelona rival
Ronaldo has started the season in blistering form with 24 goals in all competitions, 10 more than the Argentine, who was recently ruled out for up to two months with a leg muscle injury.
The pair are the leading contenders to win the Ballon d'Or - which Messi has claimed for the past four years - but the Gunners boss has hinted that he expects Ronaldo to win for the second time.
When asked for his opinion on the pair during a Twitter Q&A session, Wenger said: "It's difficult, Messi was on top until now but in the last year, maybe Ronaldo is in front, he is very athletic."
Wenger recently revealed that he came came agonisingly close to signing Ronaldo before he joined Manchester United in 2003 and even allocated the former Sporting Lisbon youngster a squad number.
The winner of the Ballon d'Or will be announced on January 13, 2014, in a ceremony held in Zurich.