The Arsenal manager feels the Real Madrid star has made a phenomenal start to the season and believes that he may have the edge over his 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 be crowned Fifa Ballon d’Or Player of the Year - which Messi has claimed the past four years - but the Gunners boss wouldn't be surprised if Ronaldo won his second prize.
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 he came came 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, Switzerland.